ORNAMENTAL PLANTS OF HORTICULTURE VALUE
Hardy trees and shrubs for special environmental conditions
Rhododendron adamsii Rheder - Rhododendron
Siberia, Far East (northern part of Kxabarovsk district). In
mountains at the timber line, in subalpine and alpine zones.
Evergreen small shrub with divaricate branches. Leaves
oblong-elliptic, 1-2 cm long, 0,5-1,0 cm wide, glabrous, matt green
above and rusty-brown beneath. Flowers 7-15 sessile in compact
trusses, pink, 1,5 cm in diameter. Flowers in June-August. Very
cold resistant. Z 3. New.
Rhododendron caucasicum Pall. - Rhododendron
Caucasus (the Great Caucasus and Transcaucasus), northern Turkey
(Lazistan). On northern rocky slopes at 1,600-3,000 m, usually on
lime free soil.
Evergreen spreading shrub about 1,0 m. Branches thick with dark
brown bark. Leaves oblong or elliptic, matt dark green, with a thin
fawn tomentum beneath, 4-12 cm long, 2-4 cm wide. Flowers 7-10 in
compact trusses, widely funnel or bell-shaped, white with light green
(later red) dotes within. In nature flowers May-July. Cold resistant,
but not very much dry resistant. The true type species with white
flowers is rare in cultivation. Z 5 (4).
The close related species is R. smirnowii Trutv., that
occurs in southwestern Caucasis. Shrub taller than R. caucasicum,
being 1,5 m high, flowers bright pink.
Rhododendron ledebourii Pojark. - Rhododendron
Siberia (Altay, southern Sayans) and Mongolia. On rocky slopes, in
clearings, along streams in forests and the subalpine zone.
Shrub 0.5-2.0 m. Branches numerous. Leaves leathery, 0.8-2.8 cm x
0.5-1.3 cm. Petiole less than blade. Flowers numerous, solitary or
2-3 in axils of previous year’s leaves. Corolla pink-violet, 3.0-4.5
cm diam. Pollen violet. Closely related to R. dauricum L.,
differing in its evergreen leaves and bright pink-lilac flowers.
Sometimes mentioned in the horticultural literature as R.
dauricum var. sempervirens. Very attractive when flowering
and in winter with evergreen leaves. Cold resistant. Z 4 (3). New.