Eastern Rhododendron Prospects
Having tried out many species of rhododendron both from commercial sources, friends, scientific institutions and collectors in the field, those that have proven hardy here in Southern Pennsylvania are recorded from certain areas in West China, East China, Japan and other limited sections in the area of their occurrence. With this background to work from the list of species in the second edition of the Series of Rhododendron has been searched for those species of the elepidote series which would seem more likely to succeed with us and which, as far as my knowledge goes, have not had a fair trial, if any, in our area.
Measured by this scale of possible hardiness alone it is reasonably certain that some of the sorts selected will not prove superlative in all other desirable characters, while others have very tempting descriptions, but practically any new hardy broad leafed evergreen is an acquisition in our clime and evaluated against the background of our own gardens, their worth may be more apparent than when grown among one of the great collections of wonderful species to be found in the more favored rhododendron areas.
Practically all the species that have proven hardy for the West China Himalayan area, come from Szechuan (probably eastern Szechuan?) and Hupeh, though R. campanulatum in some of its many forms is hardy. And these hardier types seem to be those that occur at medium elevations-say, 3000-8000 feet. The lapponicum and other high alpines from this section are just as incorrigible as from any other section. I have no hardy species from Kansu though it seems these should be tried. Perhaps it is too cold there.
In Eastern China there is such a variety of climate and terrain that there is sure to be much variation also in the hardiness of the plant life found there and we find some very hardy types and some exceedingly tender. R. fortunei and R. ovatum, both recorded from Chekiang province are of unquestionable hardiness in our plantings.
From Japan most things are either hardy or on the borderline so I think all unproven types should be tried and the same applies to Korea.
I must confess I did this bit of "Arm Chair Gardening" quite for my own prospective program but thinking it may be of interest to some of my friends-here it is.
subseries Argyrophyllum: To be tried, floribundum, fokienense, hypoglaucum, longipes, Rockii, simiarum.
Auriculatum. Just on the borderline but growable in protected sites. Seems to be considerable variation in hardiness between seedlings.
Anwheiense, maculiferum, monosematum, strigillosum.
subseries davidii-davidii, praevernum
subseries fortunei-hemsleyanum, serotinum
subseries oreodoxa-erubescens, praeteritum
Only two species of this series have proven definitely tender with us, R. californicum and R. ponticum, both of which are on the borderline. The untried R. hyperythrum from Formosa is probably tender but perhaps worth trial while R. adenopodum from Szechuan and Hupeh, ranks right at the top of the series in garden beauty and is dependably hardy. Since this series furnishes the basic hardiness in all satisfactory elepidote hybrids in these parts, the hybridist should probably explore all species and variants possible to determine their potentialities along this line.
LACTEUM, NERIIFLORUM and TALIENSE SERIES
We have tried so many species of the Lacteum, Neriiflorum and Taliense series with negative results that we do not wish to recommend any for general trial. However those who live in the milder and more protected sites of our area or who can give them good protection, will be able to grow some of the hardier types-in my opinion. These series possess many desirable characters in their many species.
The subseries souliei, which promises the only notable hardiness in this series, has been fairly well tried out and only souliei itself lives on. It can scarcely be called satisfactorily hardy but has endured some twenty years and flowers with fair regularity. I regret to record these results with such an interesting and eminently desirable group.
Unplaced species of the second edition, 1947, of the Species of Rhododendron. There are several species here from the area of West China that arouses our interest. Asterochnoum, ochraceum, platypodum and potanini might be worth a trial here.
The next 'operation' of this "Arm Chair" project is of course to obtain the plants of these species for trial. I have made no progress in it whatever to date and I feel sure many of these will be very difficult if not impossible to obtain but if we each exploit the potential sources of such material known to us we may be able to review results when next year's "AC" session comes up.
It is a little too far-or rather it just takes too much time-to go to the meetings of the New York chapter for me to attend very often, so my only contact with the Society (or now Societies) is the Quarterly and the occasional visits of interested persons. I surely would like to visit the Northwestern section some time before I get too old. I saw a number of English and European gardens in 1917, 18 and 19 while on duty in an Army Band in that area, in fact that was the beginning of my interest in these plants and my failure to grow them here as over there was the challenge that started my hybridization experiments here. Though 90%o and more of the things I got from there died and I got my real start from English friends, with a little from Holland and Germany.
I sent a lot of things to the West Coast when I found they were not hardy here, Barto, van Veen, Ostbo, Lem - then at Ketchikan, Alaska and many others obtained their first plants through me from these sources. In the lists of plant names that occur in the Bulletin the names of these things often recall those days. I would like to see the ones that failed here some time.