Rhododendron camtschaticum

by John Weagle, Halifax, Nova Scotia (Zone 6)


 

This species is more difficult to spell right than it is to grow, if you can provide the conditions it demands.

Looking at this rather rarely grown deciduous rhododendron in subgenus Therorhodion for the first time one would have a hard time deciding to which genus it belongs, though Rhododendron would surely come to mind. A very curious and beautiful rhododendron it has obovate leaves with bristly margins and leafs out periously early if you are prone to late frost in early May. Virtually prostrate in my garden it rises no higher than about 7cm. and forms a mat about 50cm. across after more than 20 years. Unlike most rhododendrons it is mildly stoloniferous. Plants with no apparent flower buds in Autumn shock and confound all with an eruption of bloom the following spring. The clever buds were there all along, neatly tucked away inside the woody stems and embedded in spring’s first green shoots. In bloom the 4-5cm flowers are reminiscent of pansies dancing above the mat on stout little pedicels, quite a magical effect.

R. camtschaticum Foto: John Weagle

The typical colour is a purplish-pink though Glendoick Gardens in Perth, Scotland and the Danes - those superb growers of everything difficult or rare - have developed good dark purple, clear pink and red forms. These we have acquired and are slowly getting established. The extremely rare white form has been lost here on three occassions by both myself and Walter Ostrom. Kind souls have given us more plants and we will certainly not be repeating our previous stupid transgressions. An added bonus is R. camtschaticum’s good fall colour in shades of orange, red and clear yellow.

Walter’s garden near Peggy’s Cove, N.S. probably provides the closest thing to perfect conditions for this species - cool foggy summers, a lack of damaging late frosts and plenty of wind. Growing in a peat bed heavily laced with sharp masonary sand and mulched with granite gravel it grows lustily and even seeds itself about. Miraculously several white seedlings appeared in his beds though they as well departed company when they unfortunately dried out. (His mother plants were grown from type seed collected on Kodiak Island, Alaska, where the first white flowered plants were found.) This species cannot tolerate extended hot humid summers or dryness combined with blistering sunshine; the white form (the very mention of which causes involuntary nail-biting) is even less tolerant. I have had little luck growing quantities of R. camtschaticum from seed; one or two survivors per packet is seen as a major coup. Barry Starling in Exeter, Devon was astounded to learn that Glendoick Gardens in Perth, Scotland routinely bloom seedlings in 14 months from seed. The following year he was blooming seedlings in 10 months. Jens Nielsen, the propagator at Glendoick, advised us to keep feeding the seedlings and young plants at quarter to half strength - even the white ones which one would expect to be susceptible to fertilzer burn!

R. camtschaticum is native to the cool areas of N. Japan, Sakhalin, Kamtschatica, the shores of the Sea of Othotsk, Kuriles, the Aleutians and S. Alaska, it is bone hardy. The Encyclopedia of Rhododendron Species by Peter A. Cox and Kenneth N.E. Cox shows some nice forms. If you have a nice cool but sunny spot in a peaty section of the rock garden you will find it rewarding indeed.

If you want a real challenge try its close relative R. redowskianum, reminiscent in bloom of clouds of tiny butterflies though a humbling plant for those with delusions of lofty plantsmanship.

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Kommentar til klassifiseringen av Rhododendron camtschaticum.

Denne planten har alltid vært plagsom for systematikerne. Man trenger ikke å være botaniker for å se at den ikke passer godt inn sammen med de andre Rhododendron-artene, men det gjelder så mange i denne svære, variable slekten.

Men denne har foruten den rare vokseformen, knopper som er helt enestående, der blomsterknoppene sitter på årsskuddene. På denne basis gjorde man en egen kategori for den, Therorhodion (= jordrhododendron). Imidlertid har der vært uenighet hvilken rang den skal ha. I min rhododendronbok har jeg klassifisert den som subgenus (= underslekt), fordi en anatom da nettopp hadde vist at knoppene hadde blomsteranlegg da de ble dannet slik som alle andre. Siden den gang har vi fått et meget kraftigere redskap til å bedømme slike vanskelige tilfeller, molekylærstudier, som kartlegger det genetiske grunnmaterialet.

Flere uavhengige studier viser entydig at den står helt for seg selv utenfor Rhododendron, og faktisk nærmere en annen slekt i lyngfamilien, Menziesia.  Den må derfor regnes som en egen slekt. På Milde har vi derfor flyttet den til lyngbedet, men den slags pirk er jo heldigvis unødvendig i vanlige hager.

Rhodoholikere må jo gjerne fortsette å bruke denne vakre planten som er så veltilpasset vårt klima, og kan dyrkes langt utenfor de områder der ”vanlige” rhododendron klarer seg.

Beste hilsener Per M. Jørgensen

 


  Den norske Rhododendronforening                             www.rhododendron.no                                   stiftet den 30.mai 1997