The Ten Best Dwarfs For the Rock Garden
Norman A. Todd
Victoria, B.C., Canada
Reprinted from the Victoria Chapter Newsletter
Rhododendron is a genus offering the gardener a high range of choice. For the alpine or rock gardener the genus is a gold mine. All rhododendron lovers are promiscuous with their advice and what follows is no exception. I've chosen to define a dwarf as a plant not more than 50 centimeters or 20 inches in height or breadth when 10 years old. Rhododendrons have a longevity at least equal to humans and will grow larger than our arbitrarily defined size, but by then we treat them as senior citizens and should go to some trouble to accommodate them. By restricting the size we effectively rule out the elepidote (non-scaly) rhododendrons. Most of the really small alpine plants are lepidotes (scaly) as they need the scales to control the high variations in moisture that occur at the high altitudes where they grow. Plants not hardy in Victoria are also not considered.
Up near the top I would put 'Rose Elf'. It is a plant which sometimes suffers from the connoisseur's disdain because of its being so easily available - seen in every garden centre. But its popularity is well deserved. It is compact; a bun, tight and even. It buds easily, comes early, withstands drought better than most and doesn't complain of our coldest Januaries. It shows its pemakoense genes in its colour by having some blue in the predominant pink. It's not a great challenge to grow, but pays its rent uncomplainingly.
Also close to the top is another hybrid seen in nearly every garden centre, 'Moerheim's Beauty'. If you don't like mauve leave this one out, but it possesses all of the good qualities of 'Rose Elf'. We might have to mark it down a bit because it is somewhat larger.
Some of the recent introductions as described in the ARS Journal evoke interest and envy but this list only considers the plants I've had experience in growing. Fairly recent introductions are Peter Cox's 'Chikor' and 'Curlew'. Both are very highly rated. I like 'Chikor' better not just because it is smaller but 'Curlew's' flowers seem to me to be too large for the scale of the plant. Also, I admit to a bias of not really liking yellow flowers with red blotches or speckling. I think they remind me of gladiola. 'Chikor' does have some red in its yellow, but it's not too noticeable. It is easy to make it look like a little bonsai tree and it looks good with dwarf conifers.
This brings up two other yellows, both of which I consider really choice. Both are hybrids and both present irrefutable counterattacks on Farrer's hang-up about hybrids having "sold their birthright for a mess of comfort". The first and the better is 'Patty Bee' a Berg cross of keiskei 'Yaku Fairy' and fletcherianum. The leaves are a clear green of thick substance arranged in neat prostrate sprays. The flowers are a clear true yellow and relatively large but not obtrusively so. The second is 'Princess Anne' a Reuthe hybrid of hanceanum var. nanum and keiskei. Its foliage has a bronzy cast in winter. It is a little harder to please but given some protection from the hottest sun should do well in the rock garden.
Both 'Patty Bee' and 'Princess Anne' have keiskei as a parent. The smallest forms of keiskei have to be ranked as the best yellow of all for the rock garden. There is some confusion as to whether there is only one clone called 'Yaku Fairy' or whether all high altitude plants from the island of Yakushima are known by this name. Anyway, it is a tight little bun; as tight as any Armeria. If grown well not a leaf shows when blooming.
For sheer refinement, elegance and finesse the little Japanese azalea kiusianum has to be among the best. The small leaves are bright green; the spring leaves being quite a bit larger than the summer ones. Its spreading form, and willingness to flower make it rival any alpine plant in desirability. It comes in a range of colours from purple through pink to white. Ed Lohbrunner grew a white one called 'Mt. Fuji' which is very dwarf and one of the best.
A list of the top ten dwarfs in most publications would include impeditum. I wouldn't contest that. It's a super plant, easy of disposition, usually puts on two or more flushes of growth until reaching the age of discretion. Its blue green leaves, almost cactus like, are interesting at any time of the year. It often blooms in the fall not as profusely as in spring but with the assurance that spring will surely follow winter. It's easy to get so no one need be without it but I have a small codicil to insert - I think I like its first cousin tapetiforme better. It's not easy to describe the reason - a little clearer flower colour, a more distinct leaf. Maybe it is only where we have them growing or perhaps the form we have that makes the difference which really is not very great.
Last, I think we have to include indicum 'Balsaminiflorum', an evergreen azalea with long narrow leaves and fully double pink flowers so tight in the centre that Pierre Trudeau could have worn it as a boutonniere. But for us it is a bit of a disaster as the deer and the rabbits think of it as highly as do most rhododendron lovers.
There is not a red on the list. If you really feel "better red than dead" try 'Ruby Hart' somewhat larger than our specifications permit but very fine indeed.