Starting my species rhododendron collection

thane(z8 Bellevue, WA)July 30, 2008

Hi everyone. Based on this thread on Rhododendron macabeanum, I got interested in species rhododendrons, and I'm starting a collection. I had several areas where I needed large evergreen shrubs/trees, and was looking for something interesting, and these were perfect.

So far I have one R. macabeanum and one R. barbatum. The barbatum has very cool purple bark.

In the fall I'm buying some from the Rhododendron Species Foundation in Federal Way. I'm getting:

2 R. arboreum ssp. delavayi - Described in their catalog as "a fine form, the very best I have seen anywhere."

1 R. facetum

1 R. clementinae - This one is slow growing and not especially easy to grow, but it was my favorite foliage among all the plants I saw at the Rhododendron Species Garden in Federal Way.

Is anyone here growing any of these species? Does anyone want to brag about their species collection? :)

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thane(z8 Bellevue, WA)

Oh, and I have nine Rhododendron macrophyllum that I got from a plant salvage in Bremerton. And one R. occidentale I picked up at the Farmer's Market in Olympia. Those are species, even if I had mentally grouped them into my "native plant" category.

    Bookmark   July 30, 2008 at 3:59PM
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alcam(z8 Pacific NW)

Thane, always good to see 'new' people getting into rhodos, especially the species. May I suggest that you join the Rhododendron Species Foundation as well as the local Chapter of the American Rhododendron Society. The guidance you'll receive from the members will be invaluable.

The 'Mac' is a good species to start with, as long as you have the room, so are your next choices.

I grow 400+ rhodos with about 25% of those being species, not a large collection compared to many I know. They can be a bigger challenge.

    Bookmark   July 31, 2008 at 6:58PM
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rhodyman(SE PA, USDA Z6)

We don't grow as many species in the East (SE PA) due to our hot moist summers and our cold dry winters. Hank Schannen and his Rare Find Nursery offer the following for growing in our area:

the native East Coast azalea species
(we can't grow occidentale)
other native East Coast rhododenron species
and many more listed starting at:

Search for 'rhododendron' and then go to page 17 to see the start of the species listings.

Here is a link that might be useful: RareFind Nursery in NJ

    Bookmark   August 1, 2008 at 11:33AM
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davidrt28 (zone 7)

thane, congratulations on starting your collection.
I'm not being an eastern-sour-grapes-because-we-can't-grown barbatum-er, but you would be advised to look into the lowest temps your area has ever had - versus your USDA zone - and then read up on the performance of the plants at those temps. I know very little about the various freezes in the PNW, but I know some areas went below -10F. Bellevue, I have no idea but IIRC it's near Seattle, and I believe that part of the PNW is not particularly known for having gone very low. I say this because I just think it would be upsetting to lose plants after 20 years.

This is just one of the articles, but if you explore the website, you can find others including a report from Harold Greer.

It would be different if you were growing cannas or something, but obviously these rhody species take a long time to achieve their maximum ornamental effect. For example here I am in zn 7a and therefore consider anything less hardy than -10F risky, although, in my research of the matter I think I might be "lucky" to be in a zn 7 area that really has never gone below about -11F or so. Some zn 7 areas in the mid-Atlantic and upper south have gone to -19F in the past 100, 50, or even 20 years.

The writer in the above link sums it up:
"One more question has come to mind. Should we take the risk of growing such species series as Grande, Falconeri, Maddenii, Irroratum and others in our Species Foundation garden in the Willamette valley as the only place? Many of these are quite spectacular, rare, and have been obtained at cost of considerable effort not to mention expense. If such a winter occurred only once in 25 or 50 years it would be too often to be caught with all our "eggs in one basket." Some of these plants do not reach their real flowering beauty before 25 years. Previously I have suggested at one of our Species Foundation meetings consideration be given to an "annex" to the Species Foundation garden near Salem in such an area as San Francisco Bay region where duplicates of these varieties could be grown with a greater safeguard against being "wiped out."

Here is a link that might be useful:

    Bookmark   August 6, 2008 at 6:38PM
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davidrt28 (zone 7)

I'd only skimmed that article before today, but, it seems the "species foundation" used to be in the Willamette valley? Or is the writer talking about another species foundation? Is it possible they moved to Federal Way Washington because the Puget sound area didn't seem to get as cold in the big freezes? I read the history at the RSF website. It was because Weyerhauser donated land in Federal Way. Still it must have seemed like fortuitous timing, as I don't think the Puget Sound area fared nearly as poorly in the 72 freeze.
Perhaps the mountains east of the Seattle area are higher and better at blocking cold than those east of Eugene Oregon?

    Bookmark   August 6, 2008 at 6:48PM
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rhodyman(SE PA, USDA Z6)

The species foundation was started by people from Vancouver and Victoria, BC, all the way down to San Francisco, CA. They even had input from Great Windsor Park, in England, and other "foreign" gardens. It started as the American Rhododendron Society "species project". This project was aimed a cataloging all species in cultivation, but led to the next logical step, a permanent collection for the ARS. Dr. Milton Walker of Eugene, OR, turned the "species project" into the "Species Acquisition List". In 1964, articles of incorporation were filed in Salem, OR, for the Rhododendron Species Foundation, completely independent of the ARS. At this time it was a group of directors and the "Species Acquisition List". Immediately cuttings were solicited. The primary sources of the material were the gardens in the UK which had been the sponsors and, hence, the recipients of the collections of many plant explorers. Since the material was coming from the UK, it was much easier to send it to Canada and the University of British Columbia became the recipient of most of the material and the location of the first plantings.

Additional plantings were on Dr. Walker's property near Eugene, OR. These were moved to Jock Brydon's property near Salem, OR. These were both temporary locations to establish the collection. In 1972, there was extensive freeze damage at the Brydon garden. Due to the cold and also the rapid growth of the garden in size and labor, it was necessary to accelerate the search for a permanent location. In 1973 talks with Mr. George Weyerhaeuser were conducted quite successfully. Weyerhaeuser offered 23 acres on the Weyerhaeuser Corporation's headquarters campus in Federal Way, WA. The Weyerhaeuser committment was so great that they accepted complete responsibility of building all facilities and completely preparing the site. In return, they just required that if the Rhododendron Species Foundation ever terminated the agreement, Weyerhaeuser could buy the entire collection.

Sufficient facilities were in place by the fall of 1974 that a head gardener, Ken Gambrill, was hired and the plants were moved from Salem to Federal Way, WA. Ken Gambrill's title became curator. In 1975, all of the facilities were completed and the planting areas had been prepared. In 1976, membership in the Foundation was opened to the public. In 1980, a master plan was finalized and formal plantings were started for the garden as a whole. In 1983, an admission fee to the garden was in place. In 1984, the Executive Director position was created and essentially the present structure was beginning to take place. Richard Piacentini was the first Executive Director. 1988-9 was a severe winter, but planning had kept losses to a minimum. Tender plants were kept in hoop houses, preventing loss. In 1989, the Pacific Rim Bonsai collection was opened.

[excerpted from "History of the Rhododendron Species Foundation" by Clarence Barrett in 1994.]

    Bookmark   August 8, 2008 at 10:38AM
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davidrt28 (zone 7)

thanks for the write up/transcription. That was interesting. I'd love to visit those gardens if I ever get out to WA stats again, and Lakewold, which I've heard has nice rhodies.

    Bookmark   August 9, 2008 at 9:54PM
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i spent hours this evening going through hundreds of species of rhododendrons, one of my all time faves! I am nervous though, because I spent all this time compiling a list of about 15 species and not sure how to even find plants as specific as this! and advice?? i would love to fill my yard with them!

here is the list which should also include augustinii and aberconwayi:

doub't i'd buy em all at once. maybe the ones that end up largest to start to give them time to grow! don't make fun, i'm an ambitious newbie and appreciate any advice! :)

    Bookmark   April 4, 2013 at 1:23AM
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A great deal depends on your particular climate. As rhodyman noted above, hot summers are as difficult for many species rhododendrons as cold winters, so the zone ratings, which are based solely on minimum temperatures, are a very general guideline only. Moderate summer temperatures such as you would find in coastal locations or high elevations are just as important as winter lows.

It's also true that many rhododendron species are more difficult to grow than the usual hybrids. Most require even more attention to excellent drainage and many, especially the large leaved types, need protection from wind in the winter and early spring. I'd suggest starting with some of the easier ones such as hyperythrum, yakusimanum, smirnowii, mucronulatum (deciduous), schlippenbachii (deciduous), keiskii, bureavii before trying any of the more difficult sorts.

The Rhododendron Species Foundation and Greer Gardens are the two best sources I know of for plants.

    Bookmark   April 4, 2013 at 6:05AM
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