Dwarf Azaleas From Germany
Matt Nosal, Calverton, New York
Reprinted from New York Chapter Newsletter
With the current interest in dwarf plants, low growing azaleas have found new popularity; not only with those who possess a certain ken for unusual plant material, but with the average home gardener who is looking for highly ornamental and low maintenance plants. Searching through nursery catalogs, one will find dwarf azaleas basically represented by the Gumpo Hybrids, the North Tisbury Hybrids, Satsuki cultivars 'Gunbi', 'Gunrei', and 'Gyokushin', and the Macranthra cultivars 'Balsamaeflora' and 'Flame Creeper'.
Also available, but to a lesser extent, is one of the true garden gems, Azalea obtusum form japonicum, or A. kiusianum, as it is usually known. This charming plant is available in the typical lavender form and in a white variant, A. kiusianum album. Recently available from several west coast nurseries are cultivars imported from Japan: 'Benisuzume', 'Hinode', and 'Shoi'. Two dwarf azaleas, presumably hybrids of A. kiusianum, are 'Good Times' and 'Kermesina'. 'Good Times' is a very compact-growing, hose-in-hose pink which is listed with miscellaneous Kurume Hybrids in Lee's The Azalea Book, but the habit of growth, foliage, flowering characteristics and hardiness certainly point to A. kiusianum as a parent. 'Kermesina' originated in Boskoop, Holland, and is usually listed with the small flowered Kurumes in Dutch nursery catalogs. It is occasionally found in American nurseries, usually masquerading under the label 'Pink Kiusianum'.
Two groups of dwarf azaleas are hybrids of A. kiusianum and various Japanese azaleas bred in Germany; the Aronense and Diamant Hybrids. The Aronense group was bred by Georg Arends of Wuppertal-Ronsdorf. About 1950, he discovered a chance seedling that is very similar to R. kiusianum, but is more compact and has brighter flower color. He named this seedling 'Multiflora' and supposedly crossed it with R. mucronatum, or perhaps some of the Arendsi Hybrids. The named cultivars of this group are dwarf, profusely-flowering plants with a larger color range than what was previously available in the Kiusianum Hybrids. They were introduced by the G. D. Bohlje Nursery of Westerstede, Germany, during the early 1960s.
The Diamant Hybrids are the result of a breeding project of Carl Fleischmann, Germany. He crossed R. kiusianum with Kurume Hybrids and obtained plants with cushion habits that are very heavy flowering. They were introduced by Johann Bruns Nursery, Bad Zwischenahn, in 1969.
Descriptive Data of kiusianum Hybrids
What follows are: the colors of the kiusianum Hybrids as defined with the use of the R. H. S. Colour Chart; information concerning foliage and growth habits; and author's comment. The "type" refers to R. kiusianum.
ARONENSIS: pale purple (RHS 74C), 1¼ inch flowers; leaves 1 inch long, ½ inch wide; growth habit mounded, rather loose when compared with other cultivars of this group.
FUMIKO: dark lavender (RHS 77B), 1 inch flowers; leaves 1¼ inches long, ½ inch wide; very low, broad growth habit. This cultivar has good winter foliage, and is very compact. Perhaps the best of the group for growth habit.
HARUKO: purple (RHS 74B), 1⅛ inch hose-in-hose flowers; slightly paler in the throat and light specks of red-purple (RHS 58A) add interest. Foliage similar to the type, but taking on a bronze tint in autumn; somewhat mounded, twiggy growth habit.
HIROKO: purple (RHS 78B), 1⅜ inch flowers; foliage and growth habit similar to type. This cultivar has the largest flowers of the group, and they are slightly ruffled. Not an outstanding color, but the ruffled petals add enough interest to make it worthwhile.
KAZUKO: deep pink (RHS 67C), ⅞ inch hose-in-hose flowers; foliage larger and paler than the type; compact, mounded growth habit.
KUMIKO: pink (RHS 61 D) with a very light blotch (RHS 61 B), 1 inch flowers; leaves 1 inch long, ½ inch wide; growth about twice as broad as tall.
MULTIFLORA: lavender (RHS 72D), ⅞ inch flowers; leaves ¾ to 1 inch long, 1½ inch wide; growth habit very twiggy, about two to three times as broad as tall. This cultivar is almost completely deciduous, retaining only very small summer leaves just beneath the flower buds. A color photo in Plate 3 of Gerd Krussman's book, Rhododendrons, supposedly illustrates 'Multiflora'; however, the photo is more typical of the cultivar "Aronensis', or the Kurume cv. 'Hatsugiri'. The plant in the photo has a very strong lavender color, and while it is hard to judge a plant from a color photograph, the habit of growth is quite unlike that of 'Multiflora'. Shown is a plant about 2½ to 3 'feet wide, and almost as tall, while plants that I have seen at the Palmengarten in Frankfurt, Germany, were 2 feet wide and less than 1 foot high.
TAKAKO: pink (RHS 62A), 1¼ inch flowers, leaves ¾ to 1 inch long, ½ inch wide; twiggy, mounded growth habit; slightly broader than tall. As more and more azalea cultivars become available, the phrase, "if it never flowered it would still be worth having", seems to be well on the way to becoming a cliché. However, before that comes about, I think it should be said about this cultivar. While A. kiusianum and its hybrids all have clean, crisp foliage that seems enhanced by the twiggy growth habits; 'Takako' has by far the most unique foliage of all. The spring foliage is very pale green, and densely pubescent, presenting the viewer a foliar appearance similar to that of Stachys lanata. Planted alongside azaleas with large, dark green leaves, or dwarf rhododendrons, or among any dwarf plants with dark green foliage, 'Takako' rewards the gardener not just at blooming time, but for several weeks thereafter.
The Diamant selections are named simply with the color description prefaced with Diamant, which is the German for diamond. They are all compact, cushion shaped plants with foliage similar to the type.
DIAMANT ENZIANBLAU (Gentianblue Diamond); lavender-mauve, 1 inch flowers. Unfortunately, not a flower color representative of the name; while there are purple and lavender gentians, the most popular are the deep blue species associated with the Alps.
DIAMANT HIMMELBLAU (Skyblue Diamond): mauve, 1 inch flowers. Again, a color that does not approach the descriptive name.
DIAMANT LACHS (Salmon Diamond): pink (RHS 51 B), 1 inch flowers. Not a particularly good cultivar since the color is not very striking.
R. 'Diamont Rosa'
Photo by Mathew Nosal
DIAMANT ROSA (Rose Diamond): pink (RHS 55B) with just the suggestion of a darker blotch (RHS 54A), 1¼ inch flowers. This is one of the better cultivars of this group; the flower color is a good pure pink, and is highlighted by the darker specks and just a little paler color in the throat.
DIAMANT RO (Red Diamond): red (RHS 57B), ⅞ inch flowers. Not a pure red; actually has a trace of purple, but gives the appearance of red as it reflects sunlight. This is very similar to the Kiusianum Hybrid 'Kermesina', having slightly smaller flowers and growth habit.
DIAMANT PURPUR (Purple Diamond): light purple (RHS 73A), ⅞ inch flowers. A good clear, light purple with just a slightly lighter throat.
DIAMANT VIOLETT (Violet Diamond): pale purple, 1 inch flowers. A washed out purple; not very showy when in bloom.
Landscape Uses of the kiusianum hybrids
Aside from their use in rock gardens, the kiusianum hybrids can be used in situations where many other azalea cultivars would outgrow their usefulness. They are ideal as facer plants for Kurume hybrids and any of the numerous available azaleas of similar growth habit. They can be inter-planted with heath and heather, and are useful with dwarf conifers. Planted in groups, they can form small feature areas in a garden setting by themselves, or they can be used with dwarf rhododendrons for texture contrast.
Many homeowners with limited space are constantly looking for the dwarf plant that is a dependable bloomer, and has good summer foliage and winter interest. The kiusianum hybrids have all that, and they are dependably hardy as well. In April 1977, a sudden drop in temperature to 15°F. devastated many of the rhododendrons and azaleas at the Rhododendronpark in Bremen, Germany; the Aronense and Diamant Hybrids showed no ill effects from this sudden cold snap. In the words of Dr. Lother Heft, Director of Rhododendronpark, "The older the Aronense and Diamant Azaleas, the hardier and more beautiful they become".
In recent years, mention of Germany of Rhododendron Society meetings brought to mind Dietrich Hobble or Victor von Martin. I think it's time for one's thoughts to turn to Georg Arends and Carl Fleischmann.