JARS v36n4 - Good Plants Found During Five Visits To Japan

Good Plants Found During Five Visits To Japan
Frank Doleshy, Seattle, Washington

This is both a letter and an article; it originated from a conversation at the ARS Annual Meeting in Washington, D.C. last May. Hideo Suzuki, member of both the Japanese and American Rhododendron Societies, told ARS Vice-president Bill Tietjen that JRS members would be happy to collect seed for the ARS if they knew what we wanted. Bill discussed this with fellow New York member Howard Kuhn while driving home from the meeting: Howard offered to take over the project, and he wrote to see if I could suggest what species to collect and where to find the best forms.
"Yes, indeed", I replied, seeing this as an opportunity to obtain wider distribution of good things Mrs. Doleshy and I have found in Japan. It occurred to me that this same information, published as a Journal article, would be helpful to members when deciding which of the JRS-collected seeds to grow. Too, the article may interest people who have grown plants from our own collections, or people who want to collect for themselves in Japan. Editor Egan approved, and the result is before you.
Not here but in a second Journal article I will discuss plant geography, i.e., how the native Japanese rhododendrons have come to be in the places where now found. This subject has grown more interesting to us with each trip to Japan, and it provides a basis for evaluating the taxonomists' classification plans.
Concerning names, I continue to use R. metternichii and R. japonicum in the accustomed sense, despite Dr. David Chamberlain's proposed substitution of "japonicum" for "metternichii". My stand is the same as that expressed in the May 8, 1982 petition from the ARS to the plant taxonomists, and I hope the pre-Chamberlain names can be formally endorsed under a new rule adopted by the International Botanical Congress in 1981. (See January, 1982 issue of the Royal Horticultural Society's Journal, The Garden p. 4. Also, if you have not yet read Dr. August Kehr's article in the last issue of our ARS Journal , I suggest you do so, very soon.)
In recommending collections from certain localities, I am giving my own choices and do not believe that other people should necessarily think these the best. The important thing is that each seed packet will give the grower a sample of the natural range of variation at a particular place where the rhododendrons appear to have some merit. He or she can then make personal choices, much as if looking at and comparing plants in the wild.
To the kind of people who will do the collecting, I suggest it is not necessary to do the entire job in one season. Many ARS members have only limited facilities for seed growing, and they could not cope with all the below-listed seeds at one time. Therefore the JRS members will be doing us a favor if they spread the work out over a period of two or even three years.
R. keiskei (Hikage-tsutsuji). Three recommendations.
1. Yakushima. (Note: Anyone planning to collect seed there should first find out whether the National Parks people allow it.)
I suggest bypassing the summit of Mt. Kuromi, where the well-known stand of R. keiskei has been depleted by over collection, and instead going to the 1734 meter mountain at Lat. 30°17' N., Long. 130°31' E. This mountain, almost due south of Kuromi at an airline distance of 31 kilometers, is reached via one of the trails radiating from Hanano-ego. Approaching the northwest side of the mountain, the trail comes close to steep granite slopes where, in May, 1970, I found small mats of R. keiskei clinging to ledges. These plants appeared the same as the diminutive ones on Kuromi.
The steep slopes would be difficult and dangerous to climb; one should go left or right around them, and I think will find low-growing R. keiskei on more gentle slopes and ridges above. Seed selected from the shortest, smallest-leaved plants is likely to produce dwarfs the equal of any from Kuromi.
Other desirable collections: Along the trail from Hanano-ego to the 1734 m. mountain, the collector will find two azaleas, perhaps the finest in Japan
High-elevation R. tashiroi (Sakura-tsutsuji), with various flower colors, for example, pale violet, pink with yellowish throat, and pure white, the last sometimes with long petals. These cannot be distinguished at seed collecting time but are all desirable.
Probably R. nudipes (Saikoku-mitsuba-tsutsuji), a staunch plant, standing gnarled but erect in windy passes where other rhododendrons creep along the ground. Flowers are pale lilac to vivid red-purple; new leaves have patterns of golden hairs on top.

2. Mt. Ichibusa, boundary of Kumamoto and Miyazaki Prefectures, Kyushu, Lat. 3218' N., Long. 13106' E. Reached by highway to Yunomae thence local road via Yuyama to vicinity of shrine, and from there a trail to the summit.
We had hoped to find R. metternichii on this mountain but did not. (See below.) The grassy summit ridge was, instead, full of low-growing R. keiskei , collected as our No. 39, November 4, 1967, 1700-1710 m. In cultivation this has turned out well; it forms a small mound, twice as wide as tall, with the characteristic ovate-elliptic leaves of southern R. keiskei and with flowers more yellow than average for this species.
Other possible collection: An azalea we did not identify, growing over the R. keiskei as a tall-shrub layer.
3. East slope of Mt. Jokoji, Shizuoka Prefecture, Honshu, Lat. 35°09' N., Long. 137°56' E. To approach this place, one may travel by railway or apparently by road; we took the train from Sakuma Dam, riding a few kilometers north to Mukaichiba station. From there, it is desirable to have a local person as guide; ours was Mr. Amano, who had worked for K. Wada and apparently for T. Yamazaki, the botanist. After taking a taxi to the end of a road extending a few kilometers east from Mukaichiba, we followed a main trail to Yamazumi Shrine, then went north toward the summit of Jokoji, crossed a 1200 m. ridge, and finally descended to the east on a slope of shattered, sliding red rock reaching the rhododendrons on a large outcrop of chert at about 900 m. Collectors should watch out for leeches reputedly able to go through shoe leather!
Although the purpose of this trip was to see R. metternichii var. kyomaruense (Kyomaru-shakunage), we were much interested in a plant of R. keiskei and collected seed of the latter as our No. 23, October 11, 1967. Leaves were the long, lanceolate shape found in the north, but were so full of bronze-red pigmentation that we at first wondered what species we had found. The leaf coloring has carried over into cultivation, and the flowers are primrose yellow with small dots and lines of red. Other possible collection: The R. metternichii var. kyomaruense , important to plant geographers. It is tall-growing and large-leaved, bearing rose-pink flowers with slightly deeper-colored edges. R. brachycarpum (Hakusan-shakunage). One recommendation.
Southwest ridge of Mt. Ishizuchi, Ehime Prefecture, Shikoku, Lat. 33°46' N., Long. 133°07' E. In 1969 the practical approach was via road from Kuma to Omogo, thence up the trail. Completion of Kuma-to-Saijo Skyline Road may have provided easier access.
While returning from southern Japan to Tokyo at the end of our 1967 trip, we stopped briefly on Shikoku and talked with Mr. Yamawaki at the Makino Botanical Garden. He mentioned R. brachycarpum on two high mountains of Shikoku amazing to us because authorities outside Japan considered R. brachycarpum a more northern plant, native to areas at least 340 kilometers from the Shikoku mountains. We therefore returned in May, 1969 to see this species, and we later obtained seed from the forestry people (No. 53, 1800 m.)
Although readily recognizable as R. brachycarpum , the plants from Shikoku seed are somewhat distinctive in cultivation. A majority have red-maroon leaf stalks, and at least one has rose-pink flowers with deeper stripes outside and brown spots inside considerably richer than the usual colors. Another collection is desirable but should consist of seed only, since this outlying population deserves protection.

R. metternichii var. metternichii (Tsukushi-shakunage) together with R. metternichii var. hondoense (Hon-shakunage). Five recommendations: 7. Shiromizu-taki, Kumamoto Prefecture, Kyushu, Lat. 32°23' N., Long. 13103' E. Reached via highway to Yunomae, thence local road to Furuyashiki and up the trail to a small valley of farms, with a ridge above. Looking for the southernmost stand of R. metternichii var. metternichii on Kyushu proper, we had first climbed Mt. Ichibusa but found only R. keiskei and an azalea, as stated above. Told of this, the maids at our inn suggested going a few kilometers northwest to Shiromizu-taki. The R. metternichii we found there, if not southernmost, is close to it; also is interesting because 15-20% of the plants have flowers with 8 or more lobes instead of the usual 7, and these flowers are almost saucer-shaped.
Our November 5, 1967 collections, at 800-950 m., were as follows:
No. 40, from a single wild plant at the top of the long, steep slope leading up to the high valley. Plants from this seed include one with 11-lobed flowers; color is a good rose-pink.
No. 41, from wild plants on the ridge above the valley. (Collected again in 1970.)
No. 42, from the plant a farmer had brought down to his garden. Buds are deep pink, flowers lighter.
2. Vicinity of Mimatayama, on west side of Mt. Kuju, Oita Prefecture, Kyushu, Lat. 33°05' N., Long. 131°13' E. The plants that supplied seed were just east of the Mizuwaketogeto-Aso highway, a few of them visible while driving past. They appeared to be growing on an old granite peak which had been nearly engulfed by lava.
A Kurume nurseryman had recommended this as particularly high-quality R. metternichii var. metternichii , and we will perhaps agree after further comparisons. Collected as No. 38, November 1, 1967, 1300 m.
3.  Kuishiyama, Kochi Prefecture, Shikoku, Lat. 33°40' N., Long. 133°31' E. (one of two Shikoku mountains with the same name). Although this is only about 12 airline kilometers north of Kochi City, the driving distance is much longer. From the road, trails lead out through the large rhododendron stand at 1050-1176 m.
The numerous old plants have gnarled trunks and huge, horizontal branches; flowers are mostly a clear pink. Plants in cultivation retain the horizontal branching pattern, also are distinctive because of the large, nearly flat leaves, covered with white hairs when young but later so smooth they glisten. In shade, the growth habit is unusually compact. Collected as No. 45, May 21, 1969.
This appears to be one of the numerous Shikoku rhododendrons which are not fully differentiated into var. metternichii or var. hondoense .

4.  Mt. Ishizuchi, reached as described above for R. brachycarpum.
The desirable source of seed is one particular stand growing on top of the southwest ridge at approximately 1800 m. Forestry people guided us there in May, 1969, and later sent seed (No. 50).
This we consider one of the finest rhododendrons we have yet seen in Japan, and it seems clearly within var. metternichii rather than var. hondoense . Leaves are narrow and convex, somewhat similar to those of the northern Honshu R. degronianum . The top surface soon becomes smooth and shining, but the lower surface retains a dense buff-to-brown indumentum. Flowers are pink with deeper striping.
As far as we could tell on a foggy day, the total number of mature plants may be only a few dozen, and we think they should be given the same protection as the R. brachycarpum which shares this ridge.

5. Kii Peninsula, Kansai District, Honshu, Lat. 33°30' to 34°20' N., Long. 135° to 136°40' E. K. Wada once told us the best var. hondoense is from Kii, and we would not dispute this. The two following seed sources appear to be equally desirable:
Zenki road, branching from Highway 169 about 40 km. northwest of Kumano, i.e., a few kilometers north of Ikehara Dam. When we visited, November 6, 1971, only 5 or 6 km. of the Zenki road was passable for automobiles; the upper part was washed out but served as a good trail. We collected our No. 541 along this upper part, 550-620 m.
Cross-mountain road linking Highways 168 and 169. This is the road that meets 168 a few kilometers south of Totsugawa and meets 169 near Shimokitayama. Rhododendrons are common on both sides of the central ridge; here we obtained our No. 544, November 7, 1971, 750-900 m. Check the road conditions before attempting this route!
Both along the Zenki road and the cross-mountain road, the rhododendrons have long, narrow leaves with thin-textured but vivid orange-brown indumentum and, in many cases, red midribs. Flower colors are rose to pink, sometimes nearly red. R. degronianum , perhaps more accurately called R. metternichii var. pentamerum (Azuma-shakunage). Two alternative recommendations:
The range of this rhododendron is a large, triangular area in northern Honshu. At both the north and southwest corners, we have seen stands of relatively compact plants. Specific places are:
Mitake, Miyagi Prefecture, Lat. 38°50' N., Long. 140°51' E. Contour map shows precise locations of rhododendrons, as well as the roads leading to them. This was the source of our No. 81, June 10, 1969, 370-440 m.
Kusatsu-Shirane, Gumma Prefecture, Lat. 36°38' N., Long. 138°32' E. This is the famous resort, easily reached. Here we obtained No. 12, October 23, 1965, and No. 529, October 30, 1971, 1400-1700 m.
These places are more than 300 kilometers apart, yet the respective seed collections have produced plants that look the same, side by side in our garden. A new collection from either place would be welcome. R. yakushimanum , perhaps more accurately called R. metternichii var. yakushimanum (Yakushima-shakunage)
Since the conservation of this plant in the wild is important, we would want seed to be collected only if legally allowable and thought to be without effect on natural regeneration. If it can be thus obtained, I think many people would like to grow it.
R. kaempferi (Yama-tsutsuji), or near. One recommendation.
Upper slopes of Takami Mountain, on the boundary of Nara and Mie Prefectures. Honshu, Lat. 34°25' N., Long. 136°05' E. Reached in less than one hour by trail from Takami Pass, on the Wakayama-Kaido Highway (Route 1 66).
This azalea, apparently a small-leaved, much branched form of R. kaempferi , grows along another trail   the one descending westward (toward Yoshino) from the summit. Compared with other azaleas, it has the most spectacular autumn foliage we have seen, with colors from purple to orange-red. Our seed collections were No. 536 and 537, November 4, 1971, 1100-1240 m.; further collection seems highly desirable.
Other possible collection: Although unrelated to rhododendrons, Tripterospermum japonicum (Tsuru-rindo) is an attractive companion plant, with red berries held high on stalks during autumn. This is plentiful on Takami Mountain.
For several of our favorite rhododendrons, I do not give specific collecting sites. This is simply because we have seen no great differences in quality from place to place, and we think any wild-collected seed would be well worth growing. Examples are R. albrechtii , R. pentaphyllum , R. quinquefolium (respectively Murasaki-yashio, Akebono-tsutsuji, goyo-tsutsuji), and R. makinoi (Hosoba-shakunage) the R. makinoi being particularly desired by U.S. growers. Besides the rhododendrons Mrs. Doleshy and I have actually seen in the wild, we would like to recommend another one for more frequent collection. This is the Japanese R. camtschaticum (Ezo-tsutsuji) which was included in the 1982 ARS Seed Exchange as a result of Mr. Hisaji Yoshioka's contribution. This grows much farther south in Japan than in Alaska or Siberia; indeed, the southernmost Japanese stands are practically at the latitude of Chico, California and Wilmington, Delaware, and they are not exposed to the extremely long summer days of the northern lands. Therefore, if this species tends to be adapted to the environment it comes from, U.S. and Canadian growers may get better results from Japanese seed than from Alaskan seed. It will be interesting, however, to find out whether plants from Japanese seed have flowers as attractive as those on plants near Nome, Alaska, found by the Mossmans and illustrated in the last issue of this Journal.
In conclusion, I want to acknowledge the help received from many people in Japan while we have been there looking for rhododendrons. Advice and encouragement have come not only from botanists and horticulturists but also from inn maids, farmers, policemen, mountain climbers, letter carriers, power station operators, and many others. This has added greatly to our pleasure and our success, and I hope the JRS seed collecting ventures are enlivened by similar experiences.