RHODODENDRONS:COLD HARDINESS, NUTRITION
RHODODENDRONS: MYCORRHIZAL INTERACTION
RHODODENDRONS: AT SWARTHMORE COLLEGE
AZALEAS: NATIVE SPECIES
AZALEAS: WITCHES '-BROOM GROWTHS
WHENCE MOUNTAIN LAUREL
PLANTS FOR MEMBERS
ANNUAL SHOW & AUCTION
DR MICHAEL A. DIRR, PhD. MERCER FELLOW
THE ARNOLD ARBORETUM JAMAICA PLAIN, MASS.
WHEN one presents a talk to a specific plant society he is never sure of what to offer or the response to expect. The Massachusetts Chapter of the American Rhododendron Society was a great group for; although my talk included things of peripheral interest, enthusiasm and questions emanated from the audience. The following text is an attempt to record some of my rambling remarks.
In the coastal area of New England, a much greater diversity of rhododendrons can he successfully cultured than in the Midwest. You may consider your climate harsh, but by comparison it resembles a banana belt. Low temperatures (-20 to -25 degrees F.) plagued most of the Midwest during the winter of 1976-77. Desiccating winds are always problematical and severely limit successful broadleaf culture unless plants are properly protected. The soils are heavy (clay based) and often poorly drained while pH may range from 6 to 7 plus. Raised beds with appropriate soil-amendments (peat, other organic materials) and chemical agents (ferrous sulfate) are often necessary. E.H. Wilson spoke of the 'iron clads' but they are not safe under midwestern conditions. Tremendous "winter burn" was evident with flower bud damage and in some cases plant loss. 'Nova Zembla', 'America' , 'Lee's Dark Purple', 'Boursalt', and 'Roseum Elegans' showed the ill-effects.
A few of the better performers include R. dauricum var. sempervirens, R. muconulatum, 'PJM' 'Pioneer', 'Herbert', 'Gibraltar' 'Polar Bear', R. poukhanense, R. schlippenbachii, 'Karens' Northern Lights Hybrids (produced by University of Minnesota Landscape Arboretum by crossing R. kosterianum x R. prinophyllum) and a few others. The deciduous types are preferable to the semi-evergreen and evergreen types simply because the problem of wind desiccation is avoided. Many of the Exbury group, Mollis Hybrids, etc., could be grown but have not been tried to any degree. 'PJM' is by far the best broadleaf performer with flower bud hardiness to at least minus 35F and root hardiness to minus 9F (hardiest of all plants tested to date).
Winter injury (cold hardiness) is something of interest to everyone in the north temperate zones. When we speak of a plant's cold hardiness it refers to that plants' ability to withstand low temperatures-nothing less and nothing more! Forget desiccation, poor drainage, improper nutrition and other variables which contribute to decline. Plant cells are injured by low temperatures in two possible ways. The first is called intracellular freezing and refers to ice crystal formation within the membrane. This type of freezing is always lethal. Supposedly this only occurs at rapid temperature drops of something like 20 F. per minute. At least one cold-hardiness researcher believes this can occur more often than most people believe. The winter browning of Thuga occidentalis is thought to be caused of intracellular freezing. More about this later. Most damage is caused by intercellular freezing. In this situation water freezes in between the cell wall areas with the resultant injury stemming from dehydration effects. Considerable research is necessary before a clear understanding of freeze injury emerges. Rapid freezing proved more injurious to leaves of Rhododendron 'Catawbiense Grandiflorum' than slow freezing, rapid thawing or slow thawing. The following table details the results of Havis's work.
His results show clearly that extremely rapid temperature drops result in permanent injury to plant cells.
TREATMENT % INJURY
Slow Slow 0
Rapid Slow 100
Rapid Rapid 95
Slow Rapid 0
Flower buds are most sensitive to low temperatures followed by stem and leaf buds. Actually, if the stem is injured, then the other parts, regardless of hardiness, are rendered biologically non-functional. It is worth emphasizing the sensitivity of flower buds to low temperatures. When breeding rhododendrons for colder climates hardiness should probably be the overriding concern. There are those who would argue for clearer reds and good yellows. The first priority should be a plant with good flower bud hardiness in the range of minus 20 to minus 30 degrees F.
Stems are much hardier than roots with an average difference of perhaps 40 degrees F. Steponkus (Cornell University) determined killing temperatures for Pyracantha and reported the shoots were killed at minus 15 degrees F, old roots at 2 degrees F and young roots at PLUS 22 degrees F. Root killing temperatures for selected rhododendrons are presented in Table 1.
Pellett has measured temperature differences between plant tissue and ambient air. On cloudy days there was no difference. However on sunny days differences as great as 25 degrees F. were noted. These types of differences would occur in evergreen rhododendrons. If cloud cover or a cold front moved in rapidly the tissue temperatures could drop sufficiently fast to result in intracellular freezing (always lethal). If this type of occurrence was repeated over the winter months the cumulative effects of dead cells would show up as browned leaves.
Bark splitting occurs on large trees as well as rhododendrons. Multiple factors are probably involved but one major contributor is the temperature difference between the air and the cambial tissue. Pellett has recorded differences as great as 40 degrees F. The warm cambial tissue would have expanded and a sudden dropping of temperature could result in contraction which might cause bark splitting. Plane trees and Norway maples are very prone to this. Take a look in your neighborhood. The injury usually occurs on the south or southwest side where the trunk is exposed to the warm sun and the greatest temperature differential would occur.
Another important consideration in growing rhododendrons or any plants that might require winter protection is siting. Pellett oriented wooden fences in North-South and East-West directions. Shrubs were then planted around the fences and tissue temperatures recorded. Where temperature fluctuations were the greatest between ambient air and tissue, the most injury occurred. The southern exposure was worst and the northern was best with east and west intermediate.
Table 1: Root killing temperatures of container grown ornamentals in winter storage. *
Species or cultivar Killing temp. degrees F.
R. prunifolium +20
R. 'Hino Crimson' +19
R. 'Exbury Hybrid' +17
R. schlippenbachii +15
R. 'Purple Gem' +15
R. 'Gibralter' +10
R. Hinodegirl' +10
R. carolinianum 0
R. catawbiense 0
R. 'PJM' -9*
From Gouin, Coop. Ext. Serv. U. Maryland, HE 1o2-76
Many people are into container growing and, unfortunately, are not familiar with the risks. Container-grown plants need protection during the winter months for roots are much more sensitive to cold than aboveground plant parts. Pellett measured the soil temperature in a container and at a depth of 3" below the field soil surface. The unprotected container temperature was +5 F. while the field soil was +21 F. Obviously many of the roots in the container medium would be killed. Refer back to the table of root killing temperatures for an idea of which species or cultivars would be injured. Storing plants in a poly-house is a common nursery practice. For the amateur, heavy mulching or the use of a cold frame might suffice.
Desiccation injury can be serious on broadleaf plants. During the winter of 1977-78 the ground was frozen in the Midwest from December to March and snow cover was insufficient. The broadleaf plants lost moisture but were unable to replace it since the soil was frozen. No matter how much water is in the soil, if it exists in a frozen state, plants cannot absorb it. The winter of 1978-79 in the Boston area could prove to be similar. I have noticed considerable winter desiccation on Mahonia, Berberis (evergreen types), Prunus laurocerasus 'Schipkaensis' , Buxus, Ilex, Gable Hybrids and others. A gardener should keep records on this type of injury and note how the degree (severity) varies from year to year depending on weather conditions.
In terms of hardiness laboratory testing can accurately approximate the killing temperatures of flower buds and stem tissues. The Arnold Arboretum is currently cooperating with the University of Minnesota Landscape Arboretum. Briefly, stem or bud tissue is collected in January or February (it must be done at this time for plants develop their greatest cold hardiness). The pieces are exposed to gradually decreasing temperatures and samples are removed at regular intervals. These plant parts are then examined for the degree of injury by various visual and/or analytical procedures. There is usually a fairly distinct break between the temperature that caused no injury and the temperature that induced permanent injury. A temperature difference of 2 to 5 degrees may not sound like a great deal but to a plant it represents the difference between life or death. Anyone interested in the cold hardiness testing should write: Dr. Harold Pellett University of Minnesota Landscape Arboretum 3675 Arboretum Drive Chaska, MN 55318 for reprints and information.
Drainage is of paramount importance for successful landscape establishment of most rhododendrons. There are a few species (R. viscosum, atlanticum, arborescens, canadense) which occur naturally in wet areas. On the University of Illinois campus, attempts to establish mass displays have failed because proper drainage was not provided. A noted horticulturist once made the comment that with some plants the hardiness can be improved by one zone if proper drainage is supplied. It may not be a case of improving hardiness but allowing a particular plant to grow vigorously thus resisting various stresses (such as cold). Inadequate drainage results in reduced aeration which may affect respiration and other aerobic processes. If the roots suffer, the above ground parts also show stress symptoms.
Rhododendron nutrition and culture have been debated for years and if you have a successful formula then stay with it. The usual recommendation concerns low pH (4.5 to 5.5) and organic or ammoniacal nitrogen sources. Carlson's Gardens Catalog states that "fertilizing is better left undone than overdone. Cottonseed meal is one of the safest fertilizers because it is slow acting. Fertilizers for acid-loving plants are good if used in moderation." In general ericaceous plants have low nutrient requirements compared to most ornamental plants. Rhododendrons may produce optimum growth when the tissue nitrogen levels range from 1.50 to 1.75 percent of dry weight. Cotoneaster and Pyracantha might require 3 to 3.3 percent for maximum growth. In simplest terms, rhododendrons do not need as much fertilizer as other plants. In my research, the ammonium form of nitrogen has proven extremely toxic to rhododendrons and other plants when applied in high concentrations (100 ppm NH4-N at every watering) The crux with ammonium fertilization is to keep the levels low. Many people have described symptoms of "fertilizer burn" which, in fact, was an expression of ammonium toxicity The ammonium ion can severely impair metabolic processes if it accumulates to any degree in plants. At the low pH ranges which are recommended for rhododendrons the ammonium form of nitrogen predominates. If the pH rises above 5.5, a conversion of ammonium to nitrate (NO3) occurs because of the presence of certain bacterial species which catalyze this reaction. This chemical change is influenced by pH which in turn affects microbial populations and species. Nitrate (NO3) can serve as an effective nitrogen form for rhododendrons. The pH increases if a nitrate fertilizer ((KNO3 or Ca(NO3)2)) is used. The most important aspect of using NO3-N is to provide an available iron form such as a chelate or sequestered iron. Nitrate is less toxic than NH4 and will promote good growth provided the other nutrients are supplied in an available form. I have grown 'PJM' in container culture with N03 or NH4 nitrogen supplied at 75 and 150 ppm. Tremendous growth resulted from the N03 fertilization while toxicity and reduced growth resulted from the NH4 -N. The crux in this work was a supply of all essential elements in an available form.
The word mycorrhizae often surfaces in relation to ericaceous plants. There is little doubt that they play a prominent part in plant survival under low fertility situations. I have collected roots from Vaccinium corymbosum, highbush blueberry, in the wild and noted extensive mycorrhizal infections. However, plants (Rhododendron, Leucothoe, blueberries) grown under high nitrogen nutrition failed to show an infection. Mycorrhizae are fungi that live if symbiosis with plant roots to the mutual benefit of host plants and fungus. Anyone fascinated by this subject should consult the following reference:
Harley, J.L. 1969. The biology of mycorrhiza. Leonard Mill, London, England. 334pp.
Mycorrhizae are probably most important in mineralizing certain essential elements, especially phosphorous. It is obvious that plants can survive without mycorrhizae. You might dig one of your rhododendrons and examine the roots. If the young roots appear swollen or flattened then there is a good chance the roots are infected. For further proof find a microscope and investigate.
Salt damage can be another problem with rhododendrons. In general, rhododendrons are very susceptible to excess soil salinity and will exhibit severe leaf burn. Salt levels above 2 to 3 mmhos (about 1200 to 1900 ppm) will induce damage. This is part of the reason for recommending low levels of fertilizer. The fertilizer you apply ((NH4)2S04, Ca(N03)2, NH4NO3, Peter's Rapid-Gro) is formulated as a salt. Too much will induce injury. This is another reason for recommending something like cottonseed meal because of its slow availability. It should be mentioned that the injury results from an osmotic effect. This means that water may not move into the plant even though there is ample water in the soil. The salt (fertilizer) which is dissolved in the soil water causes the osmotic effects.
Companion plants for rhododendrons should be of interest and for that reason I have chosen to discuss a few. Rhododendron gardens can be somewhat bland when not in flower.
Styrax japonicum- Japanese Snowbell
An especially dainty, 20 to 30 foot, multibranched tree with white, bell-shaped, pendulous flowers in May-June. Gray bark is also handsome. Easily propagated from cuttings.
Parrotia persica- Persian Parrotia
A small tree (30') of oval to rounded outline with lustrous foliage which changes to yellow-orange- red in fall. The bark develops a sycamores character and is beautiful in winter.
Stewartia pseudocamelia or S. koreana
Another small to medium-sized shrubby tree with large white flowers in late July-August deep maroon to reddish purple fall color, and superbly mottled gray to cinnamon brown color bark.
Fothergilla gardenii-Dwarf Fothergilla
Fothergilla major-Large Fothergilla
Both are superb plants, the only significant difference being size. The former grows to 3' the latter from 6 to 10'. They make dense rounded shrubs. The foliage is a leathery dark green and turns the most gorgeous combination of yellow, orange and red. Flowers appear in white, 1 4", honey-scented, bottle brush masses in late April or early May. The fothergillas are tremendous plants; unfortunately they are not well known.
Clethra alnifolia-Summersweet, Clethra
A good native plant that seems to thrive in wet or dry soils. The fragrant, white flowers span four to six weeks from July into August. The plant will sucker and form colonies. The variety rosea has pink flowers, Softwood cuttings root easily.
Aronia arbutifolia 'Brilliantissima'-Red
One of the best shrubs for fall color and persistent bright red fruits. The white flowers in May are showy but not spectacular. Height varies between 6 to 9 feet. Based on observations in the fall of 1978, this was perhaps the most spectacular fall-coloring shrub in the Arnold. It is very easy to grow but again not widely known by gardeners.
Euonymus alata- 'Compacta' Dwarf Winged Euonymus
This 8 to 10' high, densely branched, rounded shrub is often praised for its rich fall coloration. There is little doubt that it ranks among the best fall coloring shrubs but still is not as intense as the chokeberry. It does not sucker, is easily propagated from cuttings and has no serious insects or diseases.
Rhus aromatica- 'Gro-low'-Fragrant Sumac
The species is adapted to virtually any type of cultural condition, from railroad right-of-ways to shady woods. The cultivar 'Gro-low' is especially useful because it does not grow over 18" and forms a solid ground cover. The lustrous dark green foliage holds late into fall when it may assume reddish purple tints. It is easily propagated by softwood cuttings.
Mahonia aquifolium 'Compactum' Compact Oregon
This is a beautiful broadleaf evergreen with rich bronze new growth which matures to a lustrous green. In winter the foliage assumes a purplish tint. The plant grows 1 1/2 to 2' high and about twice as wide. Cuttings should be taken in November.
Hydrangea quercifolia- Oakleaf Hydrangea
This shrub might prove excessively coarse for most gardens. The large red oak-shaped leaves are leathery green and may turn a rich wine-red in the fall. The leaves are often held into November. The white flowers are borne on 8 to 12" long panicles in June-July. The flowers develop a purplish pink color with time and are effective into August-September. This species is well adapted to heavy shade.
All plants discussed will do well under cultural conditions which promote rhododendron growth. They provide colors and textures unattainable with rhododendrons. Too often when companion plants are discussed other members of the Ericaceae come to mind. The plants mentioned are serviceable and ornamental. Who knows, some of you may become so enamored by Aronia that you join that society!
Cross, James E. 1978. The winter of 76-77. To the root of the problem. Green Scene 7(1):17-19.
Govin, Francis R. 1973. Winter protection of container plants. Proc. Int. Plant Prop. Soc. 23: 255-258
Govin, Francis R. 1976. Winter injury to container-grown plants. Proc. Better Trees for Metropolitan Landscapes. USDA Forest Service. Ceo. Tech. Rep. NE-22:179-183.
Havis, John R. 1965. Desiccation as a factor in winter injury of rhododendron. Proc. Amer. Soc. Hort. Sci. 86: 764-769.
Havis, John R. 1964. Freezing of rhododendron leaves. Proc. Amer. Soc. Hon. Sci. 84: 570-574.
Havis, John R. 1976. Root hardiness of woody ornamentals. HortScience 11. 385-386.
Havis, John R., R.D. Fitzgerald and D.N. Maynard 1972. Cold hardiness response of Ilex crenata. Thunb. cv. Hetzi roots to nitrogen source and potassium. Hortscience 7: 195-196.
Patton, George E. 1977. Unusual winter tests borderline hardiness. Green Scene 6 (1) 10-12.
Pellett, Harold. 1971. Comparison of cold hardiness levels of root and stem tissue. Can. J. Plant Sci. 51: 193-195.
Pellett, Harold. 1974. Sunscald injury-influence of stem size and exposure on winter temperature of stem tissue. U. of Minn. Agr. Expt. Sta. Misc. Rept. 111. p21-22.
Pellett, Norman E. 1973. Influence of nitrogen and phosphorous fertility on cold acclimation of roots and stems of two container-grown woody plant species. J. Amer. Soc. Hort. Sci. 98: 82-86.
Steponkus, Peter L., George L. Good and Steven C, Wiest. 1976.
I. Cold hardiness of woody plants.
II. Freezing injury and cold acclimation of woody plants.
III. Root hardiness of woody plants.
IV. Using polyhouses for protection.
V. Cultural factors for overwintering. These articles appeared in the American Nurseryman from August 15 to October 15, 1976. They should be read by anyone interested in cold-hardiness.
Studer, Elaine J., Peter L. Steponkus, George L. Good and Steven C. Wiest. 1978. Root hardiness of container-grown ornamentals. HortScience 13:172-174
Rosebay Note: Dr. Michael A. Dirr is internationally known for his work as an academician and researcher. Prior to holding the coveted Mercer fellowship, he was an associate professor of ornamental horticulture at the University of Illinois. Presently he is the director of the University of Georgia Botanical Garden, Athens, Georgia. His contribution to this issue of the Rosebay is a sequel to a recent talk before the Massachusetts Chapter
BY LARRY ENGLANDER, PhD.UNIVERSITY OF RHODE ISLAND KINGSTON, RHODE ISLAND
Plant roots serve a number of important functions, not the least of which are the absorption of minerals and water, and the storage of carbohydrates manufactured by the foliage. Roots do a creditable job of supporting healthy, thriving plants, but are inefficient in one respect-- they leak. Often a large variety of harmless microorganisms are attracted into the root system's zone of influence (the rhizosphere) where they join a "soup line", eagerly awaiting unintentional handouts in the form of exudates by the plant roots. Through evolution, some fungi gave up the humble, patient ways of their companions and rather than waiting outside for a handout, instead take their sustenance by force, penetrating and invading the root.
In this latter group are the pathogenic fungi, such as Phytophthora root rot fungus, whose tiny swimming spores use rhododendron root exudates as a beacon to direct them to the root which they proceed to infect and destroy. Obviously, only the pathogen derives benefit from this interaction. But there is another relationship that has developed between certain fungi and roots, in which the fungus may penetrate root cells but not kill them. In fact, both the root and the fungus derive benefits from this association, called a mycorrhiza (see Ted Van Veen article in the Fall, 1978, Quarterly Bulletin, A.R.S.).
A peculiarity of roots of rhododendrons and other ericaceous plants is that they do not have root hairs, which are minute projections of the epidermis that compensate for their small size by occurring in great abundance, increasing root surface area and the number of sites with which the roots can "mine" for minerals and water. The absence of root hairs in rhododendrons may be partially offset by the characteristic dense fibrous root system, but substituting for root hairs on many rhododendrons throughout the world are the microscopic threads of fungi in a mycorrhizal relationship.
Although the classification of kinds of mycorrhizae is not stable, with new or intermediate types of relationships periodically being discovered, the rhododendron mycorrhizae are generally classified as ericoid endomycorrhizae, a group characterized by fungus penetration into cells on the root surface. Looking through the microscope at a young rhododendron root, one finds up to 80% of the surface cells have been penetrated by a fungus, each cell containing a "knot" of fine fungal filaments, called hyphae. Remarkably, these invaded root cells are not destroyed, but continue to function. Outside these cells there is a thin weft of hyphae acting like a microscopic root system, weaving together the plant roots and soil particles some distance away.
By investing part of its hyphae inside the root cell, the fungus benefits by obtaining essential carbohydrates without having to compete with the myriad of hungry microorganisms in the soil. The hyphae in the soil absorb water and minerals, some of which are translocated to the "knot" of hyphae inside the root cell. In some manner not yet fully understood, the root obtains from the fungus a share of these materials for its own use. This increases the plants' access to minerals, especially important when these materials are present in the soil in limited quantities.
Our knowledge about mycorrhizae on ericaceous plants has been greatly increased by the elaborate research of a group in England, directed by Dr. D.J. Read. They were able to culture a fungus which formed mycorrhizae with cranberry, heather and rhododendron, and they demonstrated under laboratory conditions that this fungus, Pezizella ericae stimulated the growth of cranberry and heather seedlings, and increased their phosphorus and nitrogen content when grown where these minerals were in a form not readily available to plant roots.
Note mycorrhizal fungus hyphas, "knot", within cell and extending into the soil. Drawing by Dr. Larry Englander
Several years ago, I began studying another fungus as a potential mycorrhizae on ericaceous plants. This study was indicated by the observations detailed below, and was encouraged by a grant from the A.R.S. Research Foundation. Each year we found large numbers of fruiting bodies of a particular fungus on the ground beneath rhododendrons and related plants. The sites, thus far only in Rhode Island and adjacent states, varied considerably, from those exposed to full sun and wind on large expanses of flat terrain, to woodland settings where shade, wind protection and natural mulch provided a more moderate environment for the plants. Soil types varied also, but generally were of low fertility. It was interesting to find the fungus fruiting beneath rhododendrons in home gardens, but there was indeed a spectacular sight to behold when visiting certain wholesale nurseries which grow large tracts of rhododendrons. There I found hundreds of these small fruiting bodies under nearly every ericaceous plant, and not a single one beneath any other plant, even when both types were interspersed in the same rows. The specificity of this fungus/plant relationship is striking. A partial list of rhododendron cultivars and species with which the fungus has been found associated appears in Table I. Other ericaceous plants found with the fungus include Kalmia latifolia, Pieris floribunda and and japonica, and Leucothoe.
Rhododendron species and cultivars.
Boule de Neige
Lee's Dark Purple
Mrs. C.S. Sargent
Mrs. P. den Ouden
The fungus fruiting bodies look like slender cream-colored stalks, generally one to two inches tall, and these occur either singly or in clusters. They first appear in the autumn, at about the time of the first frost, and continue to emerge until the deep freeze sets in. Each fruiting body produces millions of microscopic spores, which are disseminated by wind to other areas presumably to initiate mycorrhizae if they fortuitously land near the root of an ericaceous plant. Of course, these readily visible fruiting bodies comprise only the reproductive part of the fungus, the remainder being a vast network of microscopic hyphae in the soil and plant roots. The fungus has been identified as a Clavaria species, and prior to our work had not been reported as associated with mycorrhizal rhododendron roots in the United States. It was reported in Australia in 1973, on container grown azaleas.
Finding fungus fruiting bodies constantly associated with certain types of plants is not sufficient evidence that the same fungus is the one forming mycorrhizae on the roots. It was very difficult to trace hypae connecting the Clavaria fruiting body with the root due to the microscopic size of these fragile strands and the inability to see through soil particles. Another approach to verifying the mycorrhiza-forming ability of a fungus is to "synthesize" a mycorrhiza in the laboratory by combining a pure culture of the suspected fungus with an aseptically grown plant. Thus, when mycorrhizal roots develop, this constitutes evidence that the intentionally applied fungus was responsible. Since we haven't yet found a method for growing the Clavaria fungus in the laboratory, we used another method to determine whether there was a connection between its fruiting bodies and the roots--applying a radioactive isotope to one side of the plant/fungus pathway and monitoring its passage across to the other side. We utilized the phenomena that plant sugars are passed to mycorrhizal fungi, and phosphate may be transferred from fungus to plant roots.
In the first part of the study radioactive carbon dioxide (14C) was injected into plastic bags covering shoots of six-year-old plants of Pieris japonica and R. cv. 'English Roseum' growing in the field at the University of Rhode Island research farm. Clavaria fruiting bodies under these "labelled" plants were sampled after various periods of time during which the 14C was assimilated by the leaves during photosynthesis and converted to sugars which were translocated to the roots.
The mycorrbizal hyphae in these roots normally take a share of these sugars, some of which contain 14C If the Clavariafruiting bodies were part of the mycorrhizal fungus, and therefore connected to the roots, then these fruiting bodies should become radioactive as they acquire sugars, through their hyphae, from roots of the "labelled" plants.
Indeed, high levels of radioactivity were measured in fruiting bodies taken from beneath the 14C "labelled" Pieris and rhododendrons (25-fold and 121-fold increase, respectively), while weeds under these same plants, and both Clavaria fruiting bodies and weeds under untreated plants, had only background (environmental) levels of radioactivity.
In another series of tests, radioactive phosphate (32P) was applied to Clavaria fruiting bodies under two year old field grown rhododendron liners ('English Roseum') which had been transplanted to the greenhouse. Subsequently we assayed root samples from at least 23 mm below the fruiting bodies, and also roots from a point midway between the plant stem and the treated fruiting bodies. In most samples, roots were considerably more radioactive (approx. 20 to 600-fold increase) than control roots from plants with fruiting bodies that had not been treated with 32p. Additional tests showed that when 32P was applied directly to the soil surface rather than the fungus, there was no radioactivity increase of roots 12 mm or more below the surface, nor in roots at a point midway between the plant stem and the treated soil.
Thus, there appears to be an efficient two-way pipeline between mycorrhizal rhododendrons and Clavaria fruiting bodies. This supports the hypothesis that Clavaria is mycorrhizal on rhododendrons. Also significant is the ability of this fungus to supply roots with phosphorus. Roots often have only limited access to phosphate in the soil, since the insolubility of this mineral hinders its redistribution in soil water. Whether mycorrhizal roots obtain more phosphate due to the "mining" of more sites in the soil by fungus hyphae, or through the ability of the fungus to dissolve and obtain forms of phosphorus which plant roots cannot, is controversial.
Currently we are using electron microscopy to examine the effect on rhododendron root cells of mycorrhizal fungi, and found that several different fungi are probably capable of forming mycorrhizae. Other studies underway include the effect of mycorrhizae on rhododendron seedling growth rates, the inhibition of ericoid mycorrhizae by fungicides, the influence of plant culture medium composition and sterilization on time and degree of mycorrhizal establishment, and physiological investigations on nutrient uptake by rhododendrons with and without mycorrhizae. We hope to continue studying the poorly understood ericoid mycorrhizae to determine in which processes and to what degree this association is beneficial to rhododendrons, which microorganisms are most appropriate and whether or how our help may be required for initiating and encouraging mycorrhizae of ericaceous plants.
Englander, L., and R.J. Hull. 1980. Reciprocal transfer of nutrients between ericaceous plants and a Clavaria sp. New Phytol. 84 (4): (in press).
Read, D.J., and D.P. Stribley. 1975. Some mycological aspects of the biology of mycorrhizae in the Ericaceae. Pages 105-117 in: F.L. Sanders, B. Mosse and P.B. Tinker, eds. Endomycorrhizas. Academic Press, NY, 626p.
Seviour, R.J., R.R. Willing and G.A. Chilvers. 1973. Basidiocarps associated with ericoid mycorrhizas. New Phytol. 72: 381-385
Stribley, D.P., and D.J. Read. 1975. Some nutritional aspects of the biology of ericaceous mycorrhizas. Pages 195-207 in: F.L. Sanders, B. Masse and P.R. Tinker, eds. Endomycorrhizas. Academic Press, NY, 626 p.
Image Fruiting body of Clavaria. Photo Dr. Larry Englander
Rosebay Note Chapter member Larry Englander, is an assistant professor in the Department 0f Plant Pathology-Entomology at the University of Rhode Island He has worked with Phytophthoradiseases for a number of years, studying a root rot of Chamaecyparis lawsonianafor his doctoral thesis at Oregon State University.
Several years ago, Dr. Englander became interested in Mycorrhizae of rhododendron as a possible factor in root rot suppression. The results of his studies, only briefly described in his article, are very exciting-to say the least. It is both interesting to note and gratifying to learn that his original work was sponsored by a grant from our own A. R. S. Research Foundation. The latter led to a further grant from the Agricultural Experiment Station, U.R.I. and recently he presented a paper on his work at the Fourth North American Conference on Mycorrhizae. Those of you who wonder where your Research Foundation dollars go, and what they do---look no further!
THE mountain laurel which bloomed so recently in southern New England bears one of the more honored names in science. Known as Kalmia latifolia, the mountain laurel memorializes Pehr Kalm, Swedish scientist who spent from 1748 to 1751 roaming in America, especially in Pennsylvania. Kalm's book, Travels in North America, often has been described as the first detailed report on the colonies written by a trained scientist
Kalm did not make the rough sea journey to America to write a book. He came as a botanical scout for that master craftsman of natural history, Linnaeus. Kalm's principal task was to collect a few mulberry trees in Pennsylvania and take them to Sweden where the trees supposedly would furnish a food base for the silkworms the Swedes hoped to raise. The Swedes might as well have tried growing bananas. Silkworms eat Asian white mulberry leaves and always have shunned America's mulberry leaves
Kalm was not an ordinary adventurer. Linnaeus, the Swedish professor who devised the so-called binomial system still used in naming plants and animals, considered Kalm one of his finest apostles.
New England is among the favored regions where the mountain laurel chooses to grow. Although the shrub's range is described as from New Brunswick to western Florida, it is a plant that is highly selective about what soil it will grow in within that range. In general it rejects the efforts of most horticulturalists to transplant it into anything less than its native peaty, acid, fungus-laden soil.
English gardeners who consider it a personal slight when any plant refuses to flourish while they are green-thumbing it have met their match in the mountain laurel. Considered a most desirable shrub by the English, the mountain laurel so far has failed to thrive there.
Reprinted with permission from "Nature's Ways", a weekly nature column, The Massachusetts Audubon Society.
BY JEAN N. BERRY Wellesley Hills, Mass.
RHODODENDRONS admired for their elegant foliage and splendidly profuse flowers are a familiar sight in gardens today. However in 1856, when Horatio Hollis Hunnewell began his collection in Wellesley, rhododendrons, although native to this country, were rarely seen in New England-they were considered too tender to withstand our capricious climate.
For fifty years, H.H. Hunnewell built the collection, enlarging beds and refining cultivation methods, until his rhododendrons, numbering in the thousands, comprised the largest rhododendron garden in New England, and undoubtedly in the country. In his view R. catawbiense was the hardiest variety, and it became his specialty. As early as 1864, "Rhododendron Week" was celebrated by the Hunnewells in early June.
Hunnewell rhododendrons were the mainstay of the Great Rhododendron Show on Boston Common in 1873. Hunnewell himself promoted and produced the show, under the auspices of the Massachusetts Horticultural Society. Not only did viewers have an introduction to the spectacular plants, but they also gained an appreciation of naturalistic landscaping, a concept which was just becoming known. A year later, the Hunnewell summer estate, "Wellesley," had its first rhododendron festival, with visitors coming from great distances to view the massive display.
It had been previously assumed that, in order to protect these so called tender plants, rhododendrons should be placed in warm, sunny locations. After years of testing, observation, and much frustration, Hunnewell concluded that the plants required a sheltered, preferably cool northern exposure.
It became increasingly clear to Hunnewell that rhododendrons suffer more from summer drought and heat than from winter cold. He theorized that the brown leaves and dead flower buds which appear in the spring were not caused by winter temperatures but rather by early spring sun scorch and parched summer conditions. Winter protection therefore was less critical for hardy varieties than continued moisture in the summer and ample shade in the spring
To provide water during the hot weather, pipes were laid in 1870 to irrigate the Hunnewell plants. Hunnewell stressed the need for mulching to retain water.
In June 1876, Anthony Waterer, renowned English rhododendron grower, visited the Hunnewell estate and was impressed with the progress being made. In the following years, he sent several hundred varieties to Wellesley for hardiness testing.
In an article in "Garden and Forest", April 23, 1890, H.H. Hunnewell commented on the progress which had been made in American rhododendron culture. He gave credit to English horticulturists for breeding new varieties "with special reference to their hardiness combined with splendid foliage and the most gorgeous flowers." The article was followed by an editorial praising Hunnewell as the most "munificent patron of horticulture today"
Horatio Hunnewell, a founder of the Arnold Arboretum, created both an impressive expanse of beautiful landscaping and also through his patient efforts educated New England gardeners that this climate was suitable for many rhododendron varieties. In spite of disappointing losses, his research was invaluable. When he began his years of dedication to the "rose tree," little was known here about growing rhododendrons, and nothing was known about the varieties which could thrive in New England. Today's profusion of hybrid varieties had much of its basis in the work and zeal of H.H. Hunnewell. Wellesley Historical Society is grateful to Walter Hunnewell for sharing his rhododendron heritage. Historical data from Volume III, 'Life Letters and Diary of H.H. Hunnewell' and from 'Horticulture' , July, 1978.
John Cowles, whose father was Professor of Horticulture at the University of Puerto Rico at Mayaguez, had early exposure to plant cultivation. At one time during his professional career, he was on the staff of the former Dexter Estate in Sandwich, now the Heritage Plantation. The Plantation is well known for impressive rhododendron plantings. Today Mr. Cowles, in his position as chief horticulturist at the Hunnewell Estate, continues the work of hybridizing both large and small leaf rhododendrons, with an emphasis on hardiness for this area and focus on yellow blooms.
England and Oregon, which long led the field in hybridizing rhododendrons, have slowed their pace; it is now in the New England area where dramatic efforts in hybridizing are taking place. This development is attributable in great part to the work of the Massachusetts Chapter of the American Rhododendron Society and the continuing successes of the Weston Nurseries in Hopkinton, Massachusetts.
Adapted for the Rosebay from a feature which appeared in The Wellesley Townsman.
BY GERTRUDE S. WISTER Swarthmore, Pennsylvania
DURING the 1950's, John Wister, who was then director of the Arthur Hoyt Scott Horticultural Foundation of Swarthmore College, embarked on a program of Rhododendron breeding. The Rhododendron collection had become one of the most important on the campus. It included species, many of the older cultivars, many plants from Joseph Gable, a large number of Dexter hybrids and some of the newer cultivars from other American breeders.
With this wealth of material on hand, the program took shape. John Wister has always been interested in the early and late blooming kinds in all the plant groups of which he has been particularly fond. He wanted especially Rhododendrons that would flower during the first part of June, at the time of graduation ceremonies. Those are held in an outdoor auditorium, which takes advantage of a wooded slope. It is surrounded by a planting containing many rhododendrons under a canopy of tall trees and flowering dogwoods. But the rhododendrons all finish flowering by June first.
Hundreds of crosses were made under John Wister direction. Used many times were R. discolor, good selections of R. maximum and other cultivars with one or both of these in their ancestry. Other parents were a wide range of cultivars from old Ironclads to newer Dexters and Gables and other species.
When the pods of the first crosses were cleaned in the fall of 1953, the foreman came to report gloomily, "Them pods are full of nothing but dust." "Plant the dust," was the answer. The result--countless seedlings.
In the following years more seedlings joined the first ones. There was not enough room at Swarthmore to grow them all on, so many went to the John J. Tyler Arboretum. Although the Scott Foundation and the Tyler Arboretum are completely separate and independent entities, John Wister at the time happened to be part-time director at both.
Natural casualties greatly reduced the number of seedlings. As time went on, many were discarded as bud-tender, poor growers, nondescript in flower, or inferior to plants already in existence that bloomed at the same time. Comparatively few of all those hundreds of plants have been named. Some still under number are now deemed good enough to be named, too.
Many rhododendron lovers have shown a great interest in the Swarthmore hybrids. A few of the mid-season ones are popular, but probably more people are attracted to the late flowering ones that extend the rhododendron season.
And what about those June-flowering ones for Commencement time at Swarthmore College? Well, like many other colleges, Swarthmore has revamped its calendar, and Commencement comes in the latter part of May instead of early .June. But, although this reason for the breeding program has evaporated, and although it is unlikely that these hybrids will become commercially important, many of them will find their way into the gardens of rhododendron lovers who like big, handsome shrubs, and who will appreciate their late bloom.
We would like to hear how they perform in other places, and hope Rhododendron Society members will come to see them at Swarthmore and at the Tyler Arboretum.
NOTES ON SOME SWARTHMORE HYBRIDS
Sw. 58-279-'Scintillation' x haematodes. Mid-May bloom.
C-'Crowning Touch'-light apricot pink.
D-'Delkyn'-perhaps a little tender A fine plant until the winter of 1976. Two bad winters have hurt it. Light pink.
F-'Peach Brandy' -apricot pink, a little paler than 'Crowning Touch'
N-Someone must have liked this. I have no notes
Sw. 58-297A-'Lady Eleanor Cathcart' x decorum. Blooms at Tyler on June 1
Strong rose red with deeper blotch. About 25 flowers in a truss. Striking color on a good plant. We'll surely name this.
Sw. 58-299-( 'Lady Eleanor Cathcart' x decorum ) x Dexter #201-which we got from the University of Washington Arboretum under that number. It is perhaps not the same as 'Janet Blair'
C-Rose-pink with accenting blotch of sienna on upper lobe. Foliage very attractive
D-A paler rose-pink than C, with a heavier blotch.
Sw. 58-317A-maximum x (discolor x haematodes) x Dexter #8 is probably decorum x a decorum hybrid. Early June. Lovely ruffled with a faint yellow-green blotch. About 22 flowers to a truss.
Sw. 58-333A- 'Judy Spillane '-maximum x Dexter #201. Late May to early June. Five lobes, blush pink, yellow-green blotch, about 16 flowers to a truss. Super plant, heavy foliage.
Sw. 53-604M- 'July Possibility'-white maximum x 'Andorra Pink' which is probably ponticum roseum. Early to mid-June. Pale pink buds, fades to near-white flower of good size for mid-June bloomer.
Sw. 58-369-'Snow Shimmer'-discolor x (maximum x discolor) Early June at Swarthmore. About ten very large white wavy-lobed flowers to a truss. Pale yellow blotch, heart with pale yellow glow.
Sw. 53-627A-' Summer Jewel '-(maximum x discolor) x discolor. Blooms July 1 at Tyler with large white flowers with faint yellowish ochre in throat. The latest flowering hybrid of discolor with us.
New Fungus Discovered?
Editor's Note: The following letter is for real. We swear we actually read it!!
Weston Nurseries of Hopkinton
East Main Street
Weston, Ma 01748
In May 1979 my daughter bought a Rhodo-Yakesemanum plant from you to give me. I found the plant to be covered with the disease "felt fungus". I have gone over the plant twice with a toothbrush and malathion. The Rhodo still has the disease on it.
Can you suggest any way to cure the plant of the disease? Is it curable? I do not want this disease on my other Rhodos. Should I throw the plant away-return it to you? Please advise.
BY MATTHEW A. NOSAL Wading River, NY
IN recent years, some of the most sought after evergreen azaleas are those that can be considered diminutive dwarfs. I use the term diminutive dwarf to differentiate from the numerous evergreen azaleas that are sold and used as dwarf plants, but eventually must be transplanted or heavily pruned to remain valuable garden plants. To put this in perspective, a diminutive dwarf azalea is one which will grow three to four feet wide, and be no more than fifteen or eighteen inches tall after it has been in the landscape for twenty or twenty-five years.
There are approximately two thousand evergreen azalea cultivars, including those used as forcing azaleas by the greenhouse industry, and cultivars that are hardy only in the south. Of this amount, only about two percent can be considered diminutive dwarfs. Basically they are the Beltsville Dwarf Hybrids, the Gumpo cultivars, several Satsuki and Macrantha Hybrids, some of the North Tisbury Hybrids, and Azalea kiusianum clones and hybrids.
While all azaleas are good landscape plants, the diminutive dwarf cultivars can be used to a much greater advantage. For instance, many rock gardens are planted with azaleas such as Kurume Hybrids 'Hino Crimson' , and 'Coral Bells' and 'Macrantha'. The value of evergreen azaleas in the rock garden cannot be denied, but eventually the Kurumes that perhaps for ten or fifteen years looked so well are suddenly out of scale in the rockery. Other areas where these little gems (the diminutives) are ideal are in heather gardens, or interplanted with dwarf conifers for texture contrast, or for use as bonsai plants. However they are used, the gardener can rest assured that they will very seldom, if ever, require transplanting because they have grown too large, or pruning to remain attractive with adjacent plant material.
While the azaleas that are slow growing and dwarf enough to be used in these situations are the result of breeding with dwarf plants as the goal, or in the case of A. kiusianum, the selection of natural low growing forms, there are several diminutive dwarf azaleas that are the result of propagating a growth mutation to produce a new azalea cultivar.
This growth mutation, commonly known as a witches'-broom, is caused by a parasitic fungus. An abnormal, bush-like growth results, and when propagated, dwarf plants that have the basic characteristics of the normal growing plant but a miniature, are produced. Many of our choicest dwarf conifers are the result of a witches'-broom growth, principally dwarf forms of white and Scot's pine, and Norway spruce. Many gardeners are familiar with these plants and their background, but few are familiar, or even aware of azaleas with the same type of origin.
It must be pointed out that a plant propagated from a witches'-broom is in reality a sick plant, and since nature's way is to fight this fungus, there is a constant battle going on within the cellular structure of this charming dwarf. Most of the times the bad guys are winning the battle, but every once in a while the good guys get the upper hand, and suddenly normal growth will occur. To retain the dwarfness of the cultivar, this normal growth should be removed; if left on the plant, the dwarf cultivar will eventually revert to the normal type plant. Aside from normal garden cultural practices, a watchful eye for growth reversion is the only extra care plants originating from witches'-brooms require.
AVAILABLE WITCHES '-BROOM AZALEA CULTIVARS
Following is information describing the azaleas that are the result of witches'-broom growths, vis-a-vis descriptive data of the cultivar from which the sport originated.
'ITSI-GISHI': Found by James E. Cross, of Cutchogue, N.Y., and introduced by Environmentals, of Cutchogue, about 1974: sport of Macrantha cv. 'Warai-Gishi'. 'Warat-Gishi' , sometimes cataloged as Warat-Jishi' , was introduced from Japan by H. K. Beattie of the U.S.D.A. in 1929 (PI 77132); it is one of the looser, more upright growing of the Macrantha cultivars, growing to about a height of 30 ", with a spread of about 36 to 42 ". Foliage is dark green, narrow lanceolate; about 1 1/4" long, 3/8" wide. Flowers are semi-and double, 2 3/4" wide, slightly funnel-formed; bright pink (RHS 58B).* 'Itsi-Gisgi' will probably grow to about 18" tall and about 24" wide, with smaller leaves and flowers. The leaves vary in size and color, creating a nice contrast during the growing season. The spring leaves are dark green, and the largest, about 3/4" long and 1/4" wide, while the summer leaves are generally a lighter green and about 1/2" long and less than 1/4" wide, and slightly obtuse. The flowers are also smaller, 2 1/8", and the same color as the type,** While 'Wari-Gishi' will produce occasional single flowers, 'Itsi-Gishi'flowers will be evenly divided between single, semi-double and double.
'Itsi-Gishi' will also produce many fasciated branches, thus adding to its dwarf character, as these branches produce a horizontal row of growth buds that give the plant a "clumpy" appearance which is quite unusual and attractive. I have propagated these fasciations, and they root quite readily, but subsequent growth is not fascinated to the extent of making this a unique plant. This is the only azalea I have ever observed fasciation on, although Polly Hill mentions that this growth variation is seen in hybrids of A. nakaharai ("The North Tisbury Azaleas", ARS Quarterly Bulletin, Vol. 33, No. 3).
'JANKA':*** Found by the author, and introduced by Holly Heath Nursery, Wading River, N.Y., 1977: sport of 'Johanna' , a Vuykiana Hybrid introduced by Vuyk van Ness in 1966. 'Johanna' has a spreading, compact habit, and will probably grow to about 24 to 30 " tall, and slightly wider. Foliage is very dark green and glossy with a bronze tint, turn to a deep maroon in autumn. Flowers are bright red (HCC 721/1), single 2" wide. 'Janko' mirrors these qualities in miniature perfection. The spring leaves are larger than the summer leaves: the former being 3/4" long and 3/8 wide, with the elliptic shape of 'Johanna' , while the summer leaves are about half the size and obtuse. The leaves are dark green, with the same gloss and bronze tint as the type, but turn more of a bright red than maroon in autumn. The flowers are single, varying in size from 1" to 1 1/2", the same color as the type. This sport is very heavy flowering, producing clusters of flower buds, so when in full bloom is just a mass of bright red flowers.
'MINI-HAKATA': Found by the author, and introduced by Holly Heath Nursery, Wading River, N.Y., 1977: sport of Macrantha cv. 'Hakatashiro' ,an old Japanese cultivar; sometimes listed as 'Hakatahaku' 'Hakatashiro' is a broad, dense growing azalea with foliage slightly more oval than one associates with Macrantha cultivars. Flowers are white with a green wash in the blotch area, 2" wide. 'Mini-Hakata' has leaves that vary from near the size of the type, about 1" long and 1/2" wide, to very small leaves 1/2" long and 1/4" wide. The flowers are 1" wide and lack the green wash evident in the type. The growth habit is slightly upright, and it grows about as broad as tall.
'TANJA': Found by the author and introduced by Holly Heath Nursery, Wading River, N.Y., 1977; originally named 'Tina' and described in "The Vuykiana Hybrids", Rosebay, Vol. VII, No. 1; name changed to avoid nomenclature and identity confusion with the evergreen azalea 'Tina' registered with the ARS by William Guttormsen, Canby, OH. A sport of 'Christina' , a Vuykiana cultivar introduced by Vuyk van Nes in 1966, with a mounded growth habit, and leaves about 1 1/2" long and 1/2" wide, bright green in color. Flowers are 2" wide, hose-in-hose and irregularly semi-double; bright rose pink (RHS 52A). 'Tanja' has leaves 3/4" long, and 3/8 wide, occasionally the size of the type. (See same issue of Rosebay for photo of 'Janka' and 'Tanja'as comparison with their respective types. --Ed.)
WITCHES' -BROOM GROWTH SPORTS BEING EVALUATED
Following are azalea cultivars which have produced witches'-brooms that have been propagated and are currently being evaluated for possible introduction. Basic descriptive information is given for the cultivar, with whatever information is known about the sport. Most are not sufficiently old enough to present any definitive information.
Frank Arsen of Lindenhurst, N.Y. has found the following:
WEE WILLIE: a Robin Hill Hybrid: dense, compact growth habit. Leaves 1" long and 1/2" wide; flowers single, 2 3/4" with ruffled margins; light pink (RHS 38B). This is a very heavy flowering cultivar and one of the dwarfest of the Robin Hill Hybrids, so the sport holds great promise. The foliage size of the sport growth is about half that of the type, and if it flowers only half as heavily as the type, it should be a very charming and valuable dwarf.
James E. Cross has found the following:
GUMPO: A. eriocarpum clone; low, dense, compact; a diminutive dwarf in itself. Flowers white, with occasional rosy pink flakes; 2 1/4" wide with ruffled margins. There are two witches'-broom sports from 'Gumpo', described here as 'Dwarf Gumpo' and 'Mini Gumpo'. These are not official names, but are used to differentiate the sports. 'Dwarf Gumpo' has leaves about 3/4" long and 1/4" wide, with white flowers and rosy pink flakes about 1 1/2" to 1 3/4" wide; a general diminutive form of 'Gumpo'. This is a good plant, but perhaps not that different from 'Gumpo' to make it spectacular. 'Mini Gumpo', however is a gem. Very small foliage, and flowers with as much pink as white, to give a somewhat swirled effect. After several years it is only about 2" tall and 6 to 8" wide. Small enough to be used in the smallest rockery, with the smallest of alpine plants. It may someday be one of the most popular rock garden azaleas.
WATCHET: a Robin Hill Hybrid: dense, mounded, semi-dwarf growth habit:
leaves 1 1/4" long, 1/2" wide, oblanceolate. Flowers single, 3 1/2" wide; light pink (EBS 49B). The sport has leaves about half the size as the type and flowers of the same color about 2" wide, and very heavy flowering.
The author has found the following.
ARABESK: a Vuykiana Hybrid; compact, mounded habit with course foliage, giving a heavy texture appearance; leaves elliptic, 1 1/2" long and 1/2" wide. Flowers single, occasionally double, 3"; deep red (RHS 53D). The sport has small leaves, about 1/2" long and 1/4" wide, obtuse. The same foliage texture as the type is carried by the sport, and gives a bit of foliar interest to it.
GWENDA: a Robin Hill Hybrid; mounded habit; semi-dwarf, but as plant matures will need pruning to keep it as such, since it produces long shoots which give it a loose appearance. Flowers single, with wavy margins, 3 1/2"; pale lavender-pink (RHS 56 B). This particular sport has proved difficult to propagate. The foliage is pale green, as opposed to deep green foliage of the type, and hopefully it will have flower qualities that will compensate for poor foliage color.
A. nakahari, Pink Form; the pink form of this clone differs from the species not only in flower color, but is also more mounded in growth habit. Also it is a little more open, but still a dwarf azalea of merit. Flower color and shape are similar to 'Macrantha', and new growth is silvery and quite interesting. The foliage is about 3/4" by 1/4", and the flowers are about 1 1/2" wide. The sport has very hairy foliage, with minute leaves less than 1/2" long, and appears as just a tiny silver clump, with growth so small it may never produce flowers.
NANCY OF ROBINHILL: a Robin Hill Hybrid The broad, free branching growth habit, and beautiful hose-in-hose double 3 1/2" light pink (RHS 62C) flowers make this one of the best of the Robin Hill azaleas, and in fact one of the most spectacular azaleas available. Foliage is bright green, somewhat narrowly elliptic, with leaf size 1 3/4" long and about 5/S" wide. The sport has very small leaves, the largest 3/8" long and very short internodes, about 1/8". This may be one that never will form flower buds, or may not be very worthwhile considering the growth of the sport. It is being propagated only in the hope that it may produce some miniature double flowers.
PAT ERB: a Robin Hill Hybrid recently named (T 36-3); this may be the first published description of this beautiful azalea. A hybrid of ('Louise Gable' x 'Tama-giku') x 'Tama-sugata'. Beautiful shell pink flowers, 2 1/2" wide, with occasional semi-double flowers; foliage bright green, glossy; oblanceolate. Leaf size, 3/4" to 1" long and 1/4" to 3/8" wide. Plant habit dwarf, very heavy branching; probably growing twice as broad as tall. Growth sport with very small leaves, lighter green than the type.
REDMOND: a Robin Bill Hybrid; very dense, mounded, dwarf growth habit; leaves obovate to orbicular, 1" 10 1 1/4" long, and almost as wide; very dark green. Flowers pale scarlet (RHS 39B), with rosy red dots in blotch area (RHS 47B); flowers very flat faced. A superb azalea, and the sport promises to be the same, with similar foliage color and texture about half the size as the type. It also appears it will have a similar growth habit in miniature. If it blooms fairly well, this should be another gem to watch.
Most witches'-broom growths that I have observed on azaleas were on container grown plants. This is not to say that container culture has anything to do with this type of growth sport, but is simply a statement of my personal observations. Perhaps the fact that container plants are handled more often than field grown plants may be the reason for this.
Some sports root readily, others are difficult; some grow weakly, others are robust, so evaluation is necessary. Just as a breeder watches over the seedlings from a very important cross, and makes selections as the plants start to flower and their foliage and growth characteristics become evident, so must one watch over the young propagations from a witches'-broom.
Since most witches-brooms have stems of varying length and growth rate, leaf size and shape, it only stands to reason that the flower size may vary. Therefore it is important that the initial propagations be observed, and future propagation made from the best plant. In this way the propagator will insure that he is propagating and distributing only one cultivar. A slight variance in growth rate may not be important on a rooted cutting, but in fifteen years may be the difference between a plant that grows eight inches tall and one that grows one foot tall.
It also stands to reason that if a witches'-broom appears on an exceptional azalea cultivar, it holds great promise as a new dwarf azalea cultivar. However, one should not dismiss a sport that may grow on some of the common cultivars, for there may be just enough variation and dwarfness to be valuable.
Perhaps finding and propagating these sports is just the first step; using them for breeding may result in greatly increasing the variety available in diminutive dwarf azaleas.
* RHS refers to the Royal Horticultural Society Colour Chart. HCC refers to the Horticultural Colour Chart of the British Colour Council.
** The type always refers to the cultivar that the witches'-broom was growing on.
*** In pronouncing 'Janka' and 'Tanja' the j is a soft, or the Slovonic j, and pronounced as y.
Plants planted near large rocks receive far more moisture in the form of runoff during rains.
BY WALTER 0. BEASLEY, Lavonia, Georgia
It is difficult for me to discuss native azaleas without resorting to the ecstatic enthusiasm that William Bartram expressed when he rounded a bend in the Savannah River and saw "Flame Azalea" in bloom for the first time. Bartram's experience occurred a few miles from our present home. Bartram also ate fresh salmon from this river. About 200 years later calendulaceum has become a rarity and salmon extinct.
Native azaleas are coming back! Interest in the natives is very high in the William Bartram and Azalea Chapters of the A.R.S. R. canescens and nudiflorum are plentiful in the wild and are still called "Bush Honeysuckle". Our customers, who normally buy one red, one white and one pink azalea, are beginning to purchase the orange, yellow and red forms of the natives. The State of Georgia has finally adopted the native azalea as the official state wildflower.
The culture of native azaleas is pleasingly easy. We plant in a mixture of one-half rich woods earth, taken from hardwood woods, and one-half pine bark. All our plants are planted level with the ground or in raised beds. Plants for sale are grown in containers in the same mix.
Natives enjoy an abundance of water but once established are remarkably drought resistant. They respond in kind to the level of care given them. We fertilize our plants once a month with Osmocote 14-14-14 during the growing season. Our rule on this is simple--light and often.
A good 50% of natives in the wild never bloom, or bloom sparingly. Inadequate sunlight is the obvious reason for this. Our best plants are grown in 3/4 sun, or under deciduous trees where they receive full sun in the spring and shade during the hot summer. Adequate sun results in stocky plants that set multiple buds. Multiple budding means ball trusses at blooming time. Plants that flower heavily obviously need more care in the form of water and fertilizer.
Native azaleas are remarkably tough. I have seen plants, burned to the ground in forest fires, regenerate to their former size and bloom profusely in two years time. I have seen them defoliate from drought in mid summer and sucker out anew with the fall rains. Despite their toughness they are opportunists that luxuriate under good care.
NATIVES--IN ORDER OF BLOOM:
canescens: The native of my childhood that dares to bloom half
naked in the yet bare woods and break the grip of winter. Blooms white to pink and fragrance is fair to fabulous. Height 5 to 15 feet.
austrinum: Pale cream to deep orange. We have a form that is pure gold with no red in the tubes. Flowers are small and numerous, fragrance delightful Grows 5 to 15 feet and blooms in early April.
alabamense: White with yellow blotch. Dwarf, twiggy-our form is not the best. Fragrance is mild and nice.
vaseyi: White to deep pink-freckled with brown orange. Grows 5 to 10 feet and has beautiful fall foliage.
nudiflorum: Near purple to light pink. Fragrant, grows 5 to 8 feet. Ingrades with canescens are common here.
Choptank River Hybrids: From Polly Hill's find on the Choptank River (atlanticum x nudiflorum). Low- from 2 to 4 feet. Large flowers-white to good rich pinks. Fragrance is pleasantly strong and clove like. Permeates the whole garden. Plants range in height from 18 inches to 4 feet at ten years of age. We have one form that is far superior to its pod mates--a good rich pink that blooms like nothing else in the garden. Still another form is a natural dwarf- 18 x 18 inches at ten years and so dense that none of the limbs are visible when it is in leaf. The flowers on this form are snow white and extremely fragrant.
speciosum: Clear yellow through orange to blood red-flowers ~ to 2 inches across. Will set as many as 12 buds in a cluster, resulting in baseball trusses. Its hybrids with canescens will range in color from pale apricot to red-all with yellow blotches and fragrant. A collection of speciosum hybrids run the gamut of peach, pink, yellow, orange and red shades. Height is 2 to 6 feet.
calendulaceum: Flame azaleas start blooming April 15 and continue to bloom through the month of June. Blooming time seems to be determined by the altitude of origin. Flowers run large to three inches and come in all shades of yellow, orange and red. Some forms show distinct stiping at the joints of petals. Flames are not fragrant but make up for this with superior form and color. Grows 6 to 12 feet.
arborescens: Magnificent large white that blooms about the first of July for us. Some forms (probably hybrids) have showy yellow blotch. We found a group of arborescens growing at 3500 foot elevation on a dry ridge. None of the plants in the colony were over three feet high and were extremely twiggy and dense. Our normal streamside plants are 8 to 16 feet tall. By far, the best midseason white!
bakeri: The beautiful foliage and flowers have a peculiar porcelain-like sheen that makes them most attractive. They come in all shades of yellow through orange to blood red. It blooms at the same time as arborescens. Bakeri is low, normally flat topped and non-fragrant. Some of the wild "dwarf" forms will grow rapidly to 5 feet when given adequate soil, moisture and fertilizer.
viscosum: Blooms two weeks after arborescens and comes in a poor second in all other categories.
prunifolium: Blooms during the month of August in beautiful shades of orange and red. Blooms are large and showy. Easy to grow-truly a magnificent plant. Height is 5 to 15 feet.
serrulatum: A long tubed, small flowered fragrant white. Blooms August into September. Worth growing because of its blooming time.
arborescens x bakeri hybrids, arborescens x prunifolium hybrids: Bloom in June and July. The colors are white, yellow, pink, peach, watermelon, orange, and red and all combinations thereof. These two groups of hybrids will cause one to wear out one's color chart. Together they duplicate the entire color range of occidentale.
Classification: As far as I am concerned this is a job for those people who are experts. Pure species are easy. Hybrids are difficult to impossible. Twenty years ago I would have given a definite answer to all questions related to classification. Now, one would get an opinion at best. If a hybrid cannot be categorized by plant characteristics and circumstantial evidence, we simply refer to it as "probably a thus and such", relax and enjoy the beauty of the creation.
All of our plants except austrinum, serrulatum, speciosum and prunifolium come from the mountains of North Georgia and points north. Our climate in North Georgia is anything but benign. We enjoy temperature extremes from +100 degrees Fahrenheit to ‑5 degrees Fahrenheit. The winters of 1976-77 and 1977-78 were arctic like. We were frozen solid for 16 weeks in 1976-77 and 14 weeks in 1977-78. None of our native azaleas showed any ill effects from this extreme cold.
Blooming times for the natives vary with the year. About one out of three years, we will have all the early and midseason species bloom simultaneously.
Propagation: By seeds is easy. The best procedures are identical to those used in handling seed from lepidote rhododendrons. We are getting bloom buds in two years from many of our crosses. Rooting cuttings is the bad news of this business. My wife, Mary, is a superb propagator; yet, she is constantly frustrated by the whims of the natives. Rooting response varies from plant to plant, season to season. We have a lovely Flame azalea that is pale pink with a canary yellow blotch. In three years we managed to root seven plants from it. This spring we put down eighty cuttings and rooted fifty. We have found Choptank hybrids to be the easiest and speciosum to be the most difficult. We keep trying.
Propagation by root cuttings is easy and yields a high percentage of plants. When plants are dug or potted any roots that are removed are cut into 4 inch sections and placed flat down in flats of pine bark. In three months to one year these root pieces will develop tops and can be potted to grow.
Hybridization: Our son, Jeff, is our best two-eyed bumblebee. He keeps good records also. We are working on crosses using our Choptank C-l and yellows, canescens x speciosum, prunifolium x arborescens and bakeri x arborescens. Jeff's enthusiasm escalated 400% when his first hybrid bloomed. He is trying desperately to decide which clone to name after his girl friend.
During the period between 1955-1965, I took on the rewarding task of planting two million trees on worn out cotton land. It is a real joy to walk over this land and see it at peace again. The scars of abuse are healed, erosion is arrested, and native azaleas, ferns, native orchids and trilliums are coming back. One cannot live amidst the complexities of nature without developing a simple and practical philosophy. Namely, no one ever owns a plant. We are at best custodians. Our job as gardeners is to please the plant by providing its simple requirements. Wherever this attitude prevails, the garden and the gardener grow in loveliness!
Rosebay Note: Walter G. Beasley is both farmer and nurseryman. He has spent all of his life amongst the plants about which he writes. He and his wife, Mary, are the proprietors of TRANSPLANT NURSERY, a nursery highly specialized in native azaleas, as well as hybrids end rhododendron. He writes that along with Robin Hill Azaleas and Dexter Rhododendrons, natives "constitute the three faces of our madness". He is a member of both the Azalea and William Bartram Chapters of the A.R.S. and vice-president of the latter chapter.
DON'T FORGET! MASS. CHAPTER HOSTS National Convention IN 1980
Massachusetts Chapter Plants for Members Committee
R. catawbiense album, Variety 'Powell Glass'
BY ANDREW PATON, Yarmouth Port, Mass.
As you may know, for the past three years we have been trying to get more 'Powell Glass' into the hands of members. We know of only two plants in the gardens of members of the Massachusetts Chapter. An additional planting of 'Powell Glass' exists in the gardens of Robert Shanklin in Old Lyme, Connecticut.* Rob Shanklin was a friend of Edmond Amateis, who introduced 'Powell Glass'. The Shanklin's have been donating cuttings of 'Powell Glass' to our program for the past two years.
Joe Gable's introduction of 'Catalgla' (R. catawbiense album, 'Glass') was a clean white and a very desirable plant. This particular form of R. catawbiense album was found by Mr. Powell Glass on one of his plant hunting trips in the Virgin ia Appalachians. Gable propagated it for a few generations until he was satisfied that it came "true white" in color from seed. Re named it 'Catalgla' in honor of its finder and released ii for commercial distribution. 'Catalgla' proved difficult to reproduce commercially from cuttings. Each year our own batting average has improved, but we are still not over .500, and we know that we have to stick the cuttings in early July to reach that 50% mark. As a consequence, commercially 'Catalgla' has been grown from seed for the most part down through the years unfortunately mauve has crept into the white of some so-called 'Catalgla' varieties. This may have been the reason that Edmond Amateis wanted to breed the select form of Powell Glass for succeeding generations. At any rate he reproduced R. catawbiense album, Glass, for five generations by breeding it back upon itself. When he was satisfied ii was reproducing continuously a true white, with good form, he introduced his plant as R. catawbiense album, variety 'Powell Glass'
Three varieties of R. catawbiense album are in circulation. They are regarded by some rhododendron collectors as one form. They, in addition to 'Catalgla' and 'Powell Glass' include the variety, 'La Bars' White'. In a following article we will discuss the difference in these three forms, particularly in flower characteristics.
'Powell Glass' has all the hardiness qualities of R. catawbiense album plus the advantages of improved flower character and form. Those who grow it find it a most desirable plant. Because of its hardiness ii is a suitable plant for most members' gardens, possessing among its other fine qualities those characteristics of a species "at home" in its natural environment. That is, it appears to be reasonably free from degradations, which sometimes attack introduced varieties.
We are continuing to set cuttings of both 'Powell Glass' and 'Catalgla'. Each year we seem to do a little better in rooting cuttings. As we develop more experience with cutting propagation, we hope to have more 'Powell Glass' available for members. In addition we will graft more of this variety on R catawbiense rootstocks next winter.
An attempt is being made to hand pollinate 'Powell Glass'. We should have seed for distribution to members this fall. If you would like to grow on seedlings, please let us know as we want to distribute seed to a variety of growing sources.
However we propagate 'Powell Glass', it is important that this fine variety of R. catawbiense album become more widely distributed. The work which Edmond Amateis did, and from which we are all benefiting, should not pass into extinction.
* Shanklin, Robert G: "R. Catawbiense v. 'Powell Glass'. Quarterly Bulletin, A.R.S. , Vol. 29, No. 3, July, 1975.
Tips On Taking Cuttings!
Morning is the ideal time to take cuttings, as the moisture content is high following the cool night. Anytime of day will work as tong as the plant is not wilted from heat or lack of moisture
Look for healthy, green stems of medium size from the sides and particularly from the north side of the plant. Avoid stems with terminal flower buds. These do not root easily and the flower bud must be removed.
The length of cuttings will vary according to the plant. Most hybrid cuttings will be trimmed to 2 inches. Cuttings of Lapponicums (as R. impeditum) may be only a half of an inch long. On these tiny plants he certain you are getting the current year's growth and that the stems are green.
Cuttings should be carried in moisture proof plastic bags. A piece of damp towel will help preserve moisture.
Rhododendron News Portland Chapter
?NAME THIS CHAPTER?
Last year one ARS Chapter led all Chapters by increasing its membership 42%, enrolling 70 new members. Name this Chapter.
Of the 390 Associate Members in the ARS, 46 (12%) belong to a single Chapter.
Name this Chapter.
Dr. Max Resnick Awarded Bronze Medal
The Massachusetts Chapter Annual Show and Auction, held May 27, 1979 at the
Waltham Held Station, once again broke all previous records for attendance, exhibits and general interest. Especially gratifying was the large outer of non-members, present for the first time, among the hundreds in attendance. Eighteen new members joined the Chapter that day. The success of this occasion was essentially the result of the splendid effort of the entire Show Committee, headed by Eveleth Cowles, and the interest aroused by Jon Shaw's excellent rhododendron article which appeared in the Boston Glope of the previous Sunday. Kudos to all!
In a surprise ceremony, culminating in a standing ovation, President Dick Brooks presented Dr. Max Resnick with the Massachusetts Chapter Bronze Medal Award. Max was cited for his leadership as past-president and director, his role as perennial budget chairman and for the quality of excellence of the Rosebay reached under his editorship.
The day was capped with Louis Cook presiding over a spirited auction of several hundred choice hybrids and species, each of which was quickly sold.
Louis Cook Award, Best in Show, Yaku. x Mars, Willard Hunnewell
Oliver Ames Award, Best Evergreen Azalea, 'Palestrina', Dick Brooks
Bald Hill Nurseries Award, Best Red Hybrid, '#R6', Maurice Hall
Brooks Award, Best Yellow, R. laetum x zoelleri, Willard Hunnewell
Eaton Award, Best Species, R. kiusianum, white form, Bertha Atwater
Heritage Plantation Award, Best Dexter, 'Scintillation', Willard Hunnewell
Hunnewell Award, Best Deciduous Azalea, 'Exbury Old Gold', Stephen Snell
Pilkington Award, Best Consolini, '#238 Consolini', H. & E. Pilkingion
Plane View Nursery Award, Best Ironclad, 'Scott Hall', Maurice Hall
Weston Nurseries Award, Best Lepidote, 'Laurie', Dick Brooks
Rose Bay Award (Judges' Trophy), (Yaku. x Mars) x 'Jean Marie de Montague', Robert Furman
Judges: John Gwynne Maurice Ball, Bob King, Heman Howard, Dick Leonard, Andrew Paton, Stephen Snell, Stephen Tipton, Eveleth Cowles
Clerks: Marion Haffenreffer, Susan Plimpton, Loretta Wilson
Class 1. New rhododendron hybrids grown by exhibitor- (Yaku x 'Mars') x 'Jean Marie', Robert Furman
Class 2. Low growing ironclads, 'Scott Hall', Maurice Hall
Class 3 Medium and tall ironclads-
3A. Red: 'Mars' x haematodes,Maurice Hall
3B. Pink: (haematodes x 'Pygmalion' ) x fortunei, Maurice Hall
3C. White: 'Album Elegans', Stephen Snell
3D. Purple: 'Ironclad', Paul Olafeen
Class 4. Low growing hybrids-hardy to -15 degrees- Yaku x Mars, Dick Brooks
Class 5. Medium and tall hybrids- hardy to -15 degrees-
5A. Red: R6, Maurice Hall
5B. Pink: 'Rochelle', Dick Brooks
5C. White: 'Ice Cube', Paul Olafsen
5D. Purple : 'Lavender Queen', M.L. Resnick
Class 6. Low growing hybrids-hardy to -5 degrees or tenderer,'Whitney's Orange', Robert Furman
Class 7. Medium and tall hybrids-hardy to -5 degrees or tenderer
7B. Orange red: '#238 Consolini', H&E Pilkington
7C. Red: 'War Dance', Ed Brown
7E. Pink: '#337 Consolini', H. & E. Pilkington
7F. Pink with a blotch-'Mrs. Furnival', W.P.Hunnewell
7H. White with a blotch 'Sappho', Dick Brooks
7I. Lavender with a blotch-'Blue Peter', Dick Brooks
7K. Cream, yellow, orange, 'Mary Bell', Robert Furman
Class 8. Dexter hybrids
8B. Pink: 'Scintillation', W.P. Hunnewell
8D. 'Ben Moseley', M.L. Resnick
8F. Doubtful Dexters: 'Wheatley', Robert Furman
Class l0. Lepidotes-'Laurie', Dick Brooks
Class 11. Unnamed rhododendron- Unknown, Robert Furman
Class 17. Species Azalea- kiusianum, white form, Bertha Atwater
Class 18. Deciduous Azaleas-Mollis, Hugh Warmold, Stephen Snell
Class 19. Deciduous Az.-Ghents Orange-red seedling, Stephen Snell
Class 20. Exburys, Ilems,Knaphill types
20A Red shades-Unknown orange-red, Stephen Snell
20B. Pink shades-'Strawberry Ice', Stephen Snell
20C. White, cream-Unnamed white, Stephen Snell
20D. Yellow,Gold-'Old Gold', Stephen Snell
20E. Orange shades-'Gibraltar', Hardie
Class 21. Evergreen azaleas-Gables, Glen Dales, Kaempferi, Vuyks
21B. Orange shades-'Torch', Faye Lieb
21C. Pink shades- 'Mozart', Stephen Snell
21D. White-'Palestrina', Dick Brooks
21E. Violet, Purple-'Beethoven', M.L. Resnick
Class 22. Other evergreen azaleas-'Robin Hill Frosty', M.L. Resnick
Class 23. Plants in pots or tubs laetum x zoelleri, W.P. Hunnewell
Class 24. Decorative arrangements Stephen Snell
Class 26. Plants, Greenhouse Grown Yaku x Mars, W.P. Hunnewell
BY: LAURA RUSSETT Wareham, Mass.
IT happened some years ago in the Annual Rhododendron Show of our Massachusetts Chapter of the American Rhododendron Society. I arrived at Heritage Plantation early enough to join the Chapter before easing over to the Classification Committee with my three trusses. Entrants do not need to be members, but somehow I felt more "legal" and part of things. Joining the Chapter was one of the best things I have done. (Amen-Ed.) Everyone was friendly, helpful, knowledgeable and just plain delightful. The warm, informal atmosphere made exhibiting easy. I was allowed to place my own trusses and did so in the most conspicuous places available. I noticed the mounting fierce competition and also that the judges were arriving, so I respectfully withdrew from the area. It seemed that in no time at all, the judging was over and I hunted down my first entry. There it was, surrounded by beautiful inflorescence, but mine had a blue ribbon, "First Prize", on it. My eyes glazed and trance-like, I kept muttering, "I won First Prize, I won First Prize. And in the Unnamed Hybrid Class too!" Suddenly I noticed that no one was paying any attention to me, so I went on to enjoy the rest of this great event. My other two entries didn't win. This was understandable when I saw the outstanding winners. It was a good feeling to have participated in a show of such high caliber, and to have won a first prize.
When one considers the magnificent beauty of the rhododendron family, it is no surprise that the number of rhododendron lovers increases every day. My family was horticulture oriented. I can remember answering the telephone, which I could hardly reach, and telling a caller that my father was at "Hoocheekoochee Hall". The caller said, "I see. Thank You." My mother tried hard to teach me to say "Horticultural Hall". When I was old enough to help sell plants, I heard pronunciation problems others had, such as the case of the befuddled little old man who asked if I had any red "Rosydandfuffs". Be knew what he wanted and hoped that I did too. I recall telling him that he made a wise choice in that red rhododendron and that it would be a beautiful plant all year around occasionally I meet a person who declares, " I don't care for rhododendrons." I equate that remark with that of a former neighbor who used to say, "Mosquitoes never bite me."
Exhibiting and judging go hand in hand. The more we exhibit, the more we judge. We do it unconsciously. But it should be done consciously, deliberately and with all the knowledge we can find. That is why I hope to share helpful hints I have learned as a Nationally Accredited Flower Show Judge. I enjoy the thrill of exhibiting and the honor of judging. At first there were moments to forget. Once a fellow judge loudly declared, "Oh my Gawd, I just can't stand that awful shade of liver-magenta." She ought to have known better. A judge is quiet, impartial and above prejudice. Another time a judge forgot her glasses and like so many of us, hoped to get by. When it became apparent that she saw big holes in the leaves as white blossoms against the white backdrop, we had to be her "eyes". We lost one judge that day.
About a month before the Annual Show of the Massachusetts Chapter, members receive 10 or so pages of vital information on exhibiting. This includes classifications, suggestions for exhibitors, rules, flower show classes (at least 25 of these), index to show classes rhododendrons and azaleadendrons, azaleas, deciduous and evergreen-from A to 7. It is hard to find much more one can add. In this show there is included a class "Plants in pots or tubs (in bloom or not)". The National Council of State Garden Clubs (NCSGC) has decided to change "potted plants" to "container grown plants". The Horticulture Study Group of Cape Cod (not a federated club), of which I am a charter member, has decided that it will stick with "potted"-a good no-nonsense gardening term. "Containers might be abused enough to become a real pain. We all have seen these "cutesy" things of endless variety, far-out designs, hard to handle and ever harder of countenance.
In the Massachusetts Chapter it is easy to know whether you are to exhibit a truss or branch. It is clearly written. In NCSGC there remains confusion generally caused by not separating large leaf rhododendron from small leaf ones in the schedule. Anyone can see that a truss of 'PJM.' or racemosum is ridiculous, uninspiring and just plain lost. A branch is the only way to show it off. Sizes of the branch are stated in the schedule so that a small plant need not be mutilated for the show. Several years ago in a federated garden show in Waltham, a beautiful branch of PJM could have won the top award but was disqualified by the judges because it was entered as a branch while the schedule asked for a truss. In the first place the schedule should not have asked for a truss in small leaf rhododendrons. Secondly, classifications should have picked it up. It is back to the problem of error caused by insufficient knowledge. Remember, "The Schedule is the Law".
A truss is a cluster of compact flowers or fruit growing from one stem-for example: Geranium, Lilac, Perennial Phlox and Rhododendron. A truss is the type of inflorescence of the above mentioned flowers. Types of inflorescences are: corymb, cyme, panicle, raceme, spike and umbel. The umbel is the type of rhododendron inflorescence. A floret is a small individual flower of an inflorescence.
ARS point scoring is as follows:
COLOR: 20 POINTS
SUBSTANCE & TEXTURE: 15
SIZE OF FLOWER: 15
CONDITIONING LABELING, NEATNESS, CORRECTNESS: 10
Nothing in nature is perfect and that very quality of imperfection is what makes it so like-able to us. I do not believe any exhibit ever adds up to 100-perhaps to 99, but that would be tops. You will notice that Color and Foliage add up to 40%. This shows where most points are centered. Point scoring is an important system in breaking a tie. Going over points is a "nitty gritty" job and tedious. In the end, knowledge gained through experience and common sense will prevail. No doubt you have noticed that the first dress or suit you pick out in a store is the one you want. (I was going to say buy--but at today's prices?) Your eye and your brain have been trained to be selective. In the Massachusetts Chapter we are most fortunate to have real knowledgeable people as concerns rhododendrons and when we know we have the best, we have no problems.
1. We know that basically exhibiting begins with your choice of rhododendron and that botanically this includes azaleodendons and azaleas. For the show you will want those which bloom at showtime. These include varied cultivars, newer hybrids, established forms, large-leaved, small leaved, all heights and widths from tall and wide to alpine miniatures, evergreen, deciduous or in-between. Choose what you like best and what will grow best for you. Rhododendron lovers can't resist the challenge of trying to grow what is not supposed to be hardy. We create microclimates. We do our utmost and are we proud when we do succeed!
2. Prepare the $10.00 hole for the $1.00 plant, using your own sliding scale.
3. Keep the plant healthy and well-groomed. Do you really believe that a straggly, messy, unloved and neglected plant has a chance of growing up to be a beauty queen?
4. Judges realize that we do not spray unless absolutely necessary but they are still looking for the best foliage. Check for any damage frequently and deal with it promptly.
1. Cut the BEST truss, BEST umbel, BEST whorl of leaves, BEST everything, in the BEST condition and cut in the morning. I believe that the truss should be fully open with just the top bud closed at showtime, although the rhododendron rules say fully opened is acceptable, which is good because blooms are hard to control. Plan accordingly. Everything hinges on everything else. If the weather is average, cut the truss the day before the show or even several days before, whenever it is almost peak. Crush the stem end with a hammer or make several longitudinal slashes in the stem end for good water absorption. Place in deep water, watching the umbel and whorl of leaves so that they are clear and free of everything. If it is in full bloom except for the top bud, you must keep it that way by keeping it cold. Often the cellar or garage is too warm at that time of year. Your refrigerator or space begged in your florist's cold room is the only answer.
Jon Shaw told me he has kept a show truss in his refrigerator for 6-8 weeks. If he can do this, it is a great hint for the rest of us to be able to exhibit these wonderful earlier varieties and exhibit to win. Forcing is harder. My way has been to cover the truss I plan to cut with plastic, leaving plenty of airflow and room so that the plastic does not touch the umbel or leaves, and misting it off and on all day long. The sun can easily steam a truss. With practice I found out what and what not to do. The danger in this method on a cut truss is that there might be some color loss.
2. Immediately after cutting seems to be the best time for immaculate grooming. This grooming can make or break your chances of winning. Pick off any debris. Cut off any deadwood, smearing fresh cuts with soil or even eyebrow make-up, so that they will be unnoticeable. Take off any badly damaged leaves hut try to preserve that beautiful whorl of leaves. With a soft cloth and gentle suds (Ivory) wash every leaf and rinse with clear water. If you have many trusses and the foliage seems fairly clean, while protecting the umbel, swish the leaves in gentle suds and rinse in clear water. When the leaves are almost dry or dry, you can rub them gently with a nylon stocking for a legitimate shine. Never use oil. Judges spot it right away and down zooms your rating. Never use strong suds (Wisk) since they remove the natural oils leaving dull, unnatural and unhealthy looking foliage. I had washed my 2 non-winners with strong suds thinking I could safely remove the sticky gray grime left on the leaves of plants growing on the roadside which was salt-sanded by the town all winter.
3. Transport your trusses carefully. There must be no drafts, no heal, no sun, no jouncing, but water enough to pull through the trip. Our Chapter advises using an old dress box with holes punched in it to hold the trusses securely apart while resting on their leaves. The stems are wrapped with wet paper towels. I have used large open-topped "orchid tubes" with spike bases pushed into a block of Styrofoam at proper distances so that the trusses do not touch each other. The Styrofoam in turn is anchored with "Mortite" to the inside bottom of a cardboard box. Tissue paper is crumpled and tucked around each truss. With stems in water I feel better, although this system won't work with large stems. Use bricks, cinder or concrete blocks around the outside of the box and it should ride safely.
4. Label your specimen correctly on the entry card, printing all the information with a waterproof pen. Trying to identify a specimen at the last moment is an awkward job.
5. If you are placing your container, check the water level and the pose of your exhibit. If the truss wobbles, stabilize it with an unobtrusive wedge of a branch or stem in the neck of the bottle
6. Take a quick look at the competition and leave quietly. You have exhibited your BEST and that in itself is a good feeling.
1. Answer your judging invitation at once. Don't keep the Show
Committee wondering, "Are you or are you not?"
2. Keep your judging appointment to yourself. To facilitate traveling, you may be given the names and addresses of the other judges. If the committee wishes to release the names of the judges before the show, it will do so.
3. Know the area in which you are judging. The best way is to grow your own, visit nurseries, gardens, shows and keep current on the literature.
4. Arrive at the appointed time, neatly dressed for the weather and temperature. Remember eyeglasses and comfortable shoes.
5. Ask any questions when you gather together before judging.
6. When you enter the judging area, quickly go through the entire show to get the feeling and quality of it.
In summing up helpful hints for exhibiting and judging, perhaps the following are the three most important in each category:
Rosebay Note: Laura Russett knows of which she speaks! Born into a "plant family" (the daughter of Peter J. and sister of Edmund V. Mezitt) plants have always been and continue to be an integral part of her life. She is a recognized Landscape Architect, having studied at Smith College, as well as a Nationally Accredited Flower Show Judge. She participated in that capacity at the 1st International Flower Show held in Bermuda early this year.
Speaker to audience:
"My job is to speak to you. Your job, as I see it, is to listen. If you finish your job before I finish mine, please raise your hands"