A Report on R. keiskei
Hideo Suzuki, Saitama-Ken, Japan
FIG.43. R. keiskei 'Red Flair' has a red
stripe on the center back of each lobe of
the corolla. The unopened buds are also
tipped with red.
Photo by Hideo Suzuki
R. keiskei named for the Japanese botanist Keisuke Ito, is a favorite rhododendron among hobbyists in Japan. Some enthusiasts mostly collect R. keiskei only. There are a few varieties and very many forms.
The most famous and most sought after variety here would probably be R. keiskei var. cordifolia, meaning heart-like leaf, or 'Yaku Fairy' from the famous Yakushima Island the home of R. yakushimanum. Even here in Japan, 'Yaku Fairy' c.v. plants are hard to acquire. From the Bonsai culturing view point c.v. plants are highly valued by us Japanese.
To me this gem seems to be classified into two forms based on its leaf size. Both forms are extremely compact, creeping, have leaves of thick texture and grow from three to five inches in height. The only difference between the two forms is the leaf size. One has leaves one inch long which are one quarter inch at the widest point in the center. The other has leaves one and one-half inches long and one-half inch wide. The smaller leaved form with round or heart-like leaves is very rare and is considered the best by fanciers.
There are two other varieties found growing on Yakushima Island. Their leaves are of almost standard size. One is erect in habit. The other, prostrate and compact, is named R. keiskei var. procumbent.
R. keiskei var. procumbent has also been discovered on several mountains on Kyushu and Honshu, the main island of the Japanese archipelago. The difference between Yakushima's and the others is the leaf texture. All Yaku keiskei despite the size of the leaves, have thicker foliage than any others.
'Yaku Fairy' - like dwarf keiskei have been reported as growing on, several mountains in Kyushu Island, including a limited area of Ebino Plateau the place introduced as Kirishima by Frank Doleshy in his article in the Bulletin Vol. 25, No. 1, page 32). If they are cultured with much fertilizer, the foliage is apt to grow larger, although it remains by far smaller than the standard one and the plants keep their compactness. As mentioned above the leaf texture is thinner than the Yaku keiskei.
R. keiskei var. hypoglaucum a rare variety, is perhaps new to most readers. Dr. T. Makino our pioneer taxonomist, discovered this form on a mountain some 50 miles north of Tokyo. He named it var. hypoglaucum since the leaf is glaucous below. The flower is paler than the typical form, being almost white. The corolla is a little more open. Although it became extinct at the place where Dr. T. Makino had found it first, two or three other stands have been reported from different mountains. Despite the fact that the places are far apart from one another, the plants are exactly the same variety.
I once ascended a mountain to observe the growth of R. keiskei var. hypoglaucum. There was a steep rock 50 feet high where several alpinists were practicing rock-climbing at the time of my visit. The plants grew on top of the rock, a small place of 10 square feet. The strange thing is that all the R. keiskei growing on the mountain were the standard species except those growing on that rock-top.
A few years ago I discovered a form of R. keiskei that may be called 'Red Flair'. Each lobe of the corolla has a red stripe on the center of the back and some short irregular red stripes appear on the front side of one or two lobes. The new stems of this form are reddish-brown and can easily be distinguished from others. The flower seems a little smaller than the standard but the color is a little deeper.
Our common name of R. keiskei is "Hikage Tsutsuji" meaning "Shade Azalea" as it grows in most cases in the shade in the wild. I do hope, however, that its simple beauty will appeal to more and more hobbyists in the States and that it will be spotlighted as one of the stars of the Rhodies of Japan.