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Rhododendron Rootstock for Alkaline Soils. A news item in the Fall 1998 Plants and Gardens News, , the Brooklyn Botanical Garden publication, says the Federal Institute of Ornamental Plants in Ahrensburg, Germany has a patented rootstock which they claim performs well in soils with pH between 5.5 and 7.0. Lime intolerant cultivars can be grafted onto the rootstock. Several nurseries in Germany are licensed to sell plants with the patented rootstocks. These plants called "Inkarho" rhododendrons are not yet available in North America.

Oldest Rhododendron Update. The last Rhododendron and Azalea News had several messages regarding the "hunt" for the oldest rhododendron.

I read with interest your query, and Harold Greer's reply, in the latest issue of R & A News. There must be many rhododendron specimens of two hundred plus years in Europe, especially in Britain, where they have long been cultivated. In the Americas, the oldest cultivated specimens may well be in the Boston area. Mr. H. H. Hunnewell of Wellesley, Massachusetts, started planting them at his estate in the 1850's and 1860's, and staged an exhibit of large plants on Boston Common in 1873. Some of the original plants, I am sure, still exist on the property. There are a number of other plantings in this area. One I know of, Moraine Farm in Beverly, Massachusetts, was laid out by Frederick Law Olmsted in 1882, and I was able to see these more than one hundred year old plants a few years ago, shortly after they had been cleared of weedy vegetation which had overgrown them. They were magnificent!

Of course, plants growing in the wild can easily have attained much greater age. There must be specimens of R. catawbiense and R. maximum in the southeast, and R. macrophyllum in the west, that make the oldest cultivated plants look like youngsters.

I am editor of the Newsletter (Tennessee Valley Chapter) of a regional chapter of the American Rhododendron Society (ARS) and a hobby grower of azaleas and rhododendrons in my retirement years. A year or so ago I read with considerable interest your papers on the damage to flower buds of R. nudiflorum by the gall midge Dasineura. I was reminded of this today when I read an appeal in the ARS online newsletter from a member for information on what insect might be causing damage to azalea seedpods. The text of this request was as follows:

"A Question About Empty Seedpods." For the last several years I have noticed some seedpods of our native azaleas had a tiny barely perceptible hole in the side and most, if not all, of the seed was destroyed. This occurred infrequently and wasn't a concern until last year when at least 90% of the seed was destroyed on what was the former Henry Skinner property. Henry had some spectacular native azalea hybrids that he developed, and, in spite of one of the heaviest seed set I have ever seen, there was virtually no seed available. I have sent seed samples off to our NC AG Extension service to no avail. They feel the hole is an exit hole from a minute insect and they are waiting for samples with the insect still inside. Has anyone any idea which insect could be causing this problem? What a disaster this could be for hybridizers. After successfully making a cross and waiting for the seed to develop, one would get quite upset to find the seed useless. HELP....Ed Collins"

Sounds to me like it might be a gall midge. What do you think? Any thoughts would be greatly appreciated. Thanks for listening. Tom Hughes

Tom: Thanks for the input but the Rhodo Tip Midge only attacks the flower. The damage is a rather ugly twisted contorted leaf and seems to do no real harm. I have just received aninput from a friend that it may be a Eurytomid seed chalcid; a tiny wasp that has become a seed specialist. I have E-Mailed someone at NC State that is supposed to be working on the one that hits native azaleas. I am eagerly waiting some feedback and when I receive it I will notify each of you. Ed Collins

Was there frass in the pods? Can you send him a few samples? Maybe your luck will be better this year. Below is Dr. Gagne's response:

I can't say what could be causing the damage to azalea pods without seeing it. I don't know of any gall midge in the seedpods, but anything is possible. It could be beetles, too, which make exit holes, but they leave frass inside which gall midges do not. Is there any way I could get some examples of the damage, or is it already too late? I'm happy to try to help. Ray Gagne"

I read with a good deal of interest your memo in the latest issue of R & A News. The varmint (whatever it is) has been busy in these parts also, for several years now. He seems to go for the native deciduous azaleas only, R. prinophyllum, R. arborescens and R. calendulaceum, but leaves R. canadense and R. vaseyi alone. I mentioned the problem to an entomologist friend in our local horticultural club, and he had never heard of these symptoms. I'll bring him a few capsules this fall to see if he can isolate the culprit. In the meantime, if you can find out anything more, I'd appreciate hearing about it.

Just a note to let you all know where we stand regarding the azalea seed pod problem. An entomologist has suggested the insect may be a Eurytomid seed chalcid; a tiny wasp with parasitic ancestry that has become a seed specialist. He gave me the name of another entomologist that may have studied the same insect and I have recently sent her an e-mail message and am waiting for a reply. AND last Monday I went to Copper Bald to check the seed crop. The first seed pod I picked had no visible hole. When I broke it open, the stinker was there. There was a very small larva about one-fourth inch long. I then found several pods with the insect still inside. I will send them off when I get a reply. Keep your fingers crossed. Ed Collins

Rhododendrons which are endangered have been identified by one of the world's oldest international conservation organizations, the IUCN. The IUCN was established in Fontainebleau, France on October 5, 1948, as the "International Union for the Protection of Nature" or IUPN. Today it is a union of governments, government agencies, and non-governmental organizations working at the field and policy levels, together with scientists and experts, to protect nature. Its mission, formally stated, is "To influence, encourage and assist societies throughout the world to conserve the integrity and diversity of nature, and ensure that any use of natural resources is equitable and ecologically sustainable. " One of its more familiar activities is publication of the IUCN Red List of Threatened Plants, often referred to as the "IUCN Red Book"...There are 62 rhododendrons listed in the 1997 edition of that book in several categories ranging from "Extinct" to "Rare".

Following are two lists of rhododendrons included in the "Endangered" and "Vulnerable" categories by the IUCN.

I. Rhododendrons Considered Endangered, i.e., " Taxa in danger of extinction and whose survival is unlikely if the causal factors continue operating. Included are taxa whose numbers have been reduced to a critical level or whose habitats have been so drastically reduced that they are deemed to be in immediate danger of extinction."

II. Rhododendrons Considered Vulnerable, i.e., "Taxa, believed likely to move into the 'Endangered" category in the near future if the causal factors continue operating. Included are: taxa of which most or all of the populations are decreasing because of over-exploitation, extensive destruction of habitat or other environmental disturbance; taxa with populations that have been seriously depleted and whose ultimate security is not yet assured; and taxa with populations that are still abundant but are under threat from serious adverse factors throughout their range."

(Printed with permission of Tom Hughes, Editor, Tennessee Valley Chapter Newsletter, August 1998)

Every person who has a rhododendron in the garden will want to look at this site. Caution: The materials and conditions are for use in the state of Washington so use with caution for your area. Click http://pep.wsu.edu/hortsense/rhody.html to view.

The Research Committee of the American Rhododendron Society wishes to announce an annual award competition for research on rhododendrons and azaleas. The deadline for submitting applications is March 15, 1999 and awards will be made by July 1, 1999 for those applications deemed to be most deserving of support. ARS research grants are intended to fund projects of limited scope or to provide "seed money" for larger studies. Traditionally, these awards have not exceeded $3,000. These funds may be used over a period of one to three years, at the discretion of the recipient, except that funds may not be used for institutional overhead. Grants are provided by the Research Foundation of the American Rhododendron Society with the understanding that research results will be published in the Journal American Rhododendron Society, a refereed publication. A sample copy and ‘Guidelines for Authors of Research Papers’ may be obtained from Ms. Sonja Nelson, Editor, 1075 Josh Wilson Rd., Mt. Vernon, WA 98273. Those applicants unfamiliar with research already reported in the Journal may also benefit from reviewing back issues of the journal, which are available in many horticultural libraries.

Proposals are evaluated by the ARS Research Committee in light of the proposals potential interest to the Society’s members and the probability of successful accomplishment of the project goals.

Up to four pages of supplemental information may be submitted with completed proposals. Thirteen copies of each proposal and any accompanying information should be sent to:

Dr. Benjamin D. Hall

Chairman, ARS Research Committee

Dept. of Botany, Box 355325

University of Washington

Seattle, WA 98195-5325

Phone: 206-543-1100

email: benhall@u.washington.edu

Click here to download an application form to apply for a grant from the American Rhododendron Society Research Committee. Grant Form.

RECENT PROPOSALS FUNDED show Project Organizer, Title of Project and Amount.

The following information was provided by Dr. Benjamin Hall, Research Committee Chairman:

Amy Denton (1997). Foliage has collected extensively at three areas in Tibet for R.Wardii, R.campylocarpum and their hybrids. In the laboratory the genetic variability within this group is evident. Molecular studies are continuing. An account of this collecting trip is in the Fall 1998 issue of the Journal, ARS in the article by K. White and R. Zimmerman.

Arora (1998) and H. R. Helm (1997) have published articles in Journal American Rhododendron Society on their projects within the last year.

David Rankin (1997) has collected rock, soil and plant material at multiple sites in Yunnan for metal analysis and measured soil pH values at each site. His report says: "It is already clear that some species of Rhododendron grow well on soil which is alkaline, rich in limestone, with a high calcium: magnesium ratio and little organic content."

The Region of Great Britain and Ireland of the International Plant Propagators’ Society has been working with countries in Eastern Europe. In a newsletter of the North American Regions of the IPPS, there is a summary of a paper from a meeting held in Poland in March 1997. The paper, "Acclimation of Some Micropropagated Rhododendron Cultivars to the Nursery Growing" was by Krystyna Bojarczuk from the Instytut Dendrologii PAN w Korniku (Institute of Dendrology in Korniku, Poland). The purpose of the experiment was to evaluate the response of Rhododendron cultivars to the microculture environment and the growth of plantlets in greenhouse and outside conditions with high relative humidity. Best growth results were obtained when treated with fertilizers and a mixture of giberellic acid and benzyloaminopurine. The number of basal branches and the lateral branch length of plants were greater than in plants propagated by tissue culture than for plants propagated by cuttings or grafting. The winter rhododendron plants for all the plants survived best in a cool greenhouse or in beds covered with sawdust. (Summarized from "Research Reports," in Official Newsletter of the North American Regions, International Plant Propagators’ Society, Volume 10, Number 2, 1998)

We are currently studying the management of root weevils in nursery sites. It is important that researchers have a thorough understanding of the impact of root weevils in nurseries in the Northwest and are aware of current nursery practices to control them. This questionnaire has been designed to gain information from growers and other individuals that have had experience with this pest. If you grow Rhododendrons, a key host of root weevils, we request that you complete the questionnaire. The information in the survey will be confidential; individuals, nurseries and companies will not be identified.

If you are interested in completing this questionnaire, please contact Robin Rosetta or Sven Svenson at the address listed below.

Robin Rosetta: email: robin.rosetta@orst.edu

Sven E. Svenson: email: sven.e.svenson@orst.edu

North Willamette Research and Extension Center

Oregon State University

15210 NE Miley Road

Aurora, OR 97002-9543

Phone: 503-678-1264

FAX: 503-678-5986

Wanted: Information. Dr. Ole R. Vetaas from the Botanical Institute, Bergen, Norway in an email message to Kristi O’Donnell, Meerkerk Botanical Gardens wrote: "I would appreciate some information on geography, climate, and survivorship of the following Rhododendron taxa in different gardens.

There is a short questionnaire which will help in my research. If you have any of the above in your garden, please contact me at: Dr. Ole R. Vetaas, Botanical Institute, Allegt. 41, N-5007 Bergen, Norway. FAX:+47 55589667. Email = Ole.Vetaas@bot.uib.no. You may download the questionnaire from this Website: http://home.sol.no/~hgrimsla/rhodo/arboret/arborete.htm click at Rhododendron research (home.sol...../query1.htm) or look for Norwegian Arboretum - Milde under www-link ARS home page. Ole has a websit. It is Rhododendron Research Project at http://www.uib.no/people/nboov/. It describes a project which tries to compare climate limits for Rhododendron species in the Himalayas (Nepal) with climatic conditions in the arboreta where the species are growing.

THE AMERICAN RHODODENDRON SOCIETY WELCOMES NEW MEMBERS.

FOR INFORMATION CLICK: ARS

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