by Evelyn Weesjes
Steve Hootman, Director and Curator of
the Rhododendron Species Botanical Garden north of Tacoma, Washington, returned
once again, this time to talk on ‘Dwarf
Rhododendron Species’. Steve
started working at the R.S.F. garden in 1992 and in the eight years intervening
he became responsible for overseeing their rhododendron collection and made
four expeditions to the Himalayan region to see and collect more species. The Rhododendron Species garden is 36 years
old and has the second best species collection after Edinburgh, Scotland.
In
their native habitat, dwarf rhododendrons are mainly alpines growing above
timberline in scree or open meadows in bright light on the mountains. The growing season is short, temperatures
are cool and melting snow and rainfall provide ample moisture. In cultivation, they require bright light, a
coarse organic well-drained soil and light shade from the heat of the afternoon
sun in summer
Early
plantings in the R.S.F. garden used a deep layer of sawdust in the beds in
which to plant the species. Over time
the sawdust decomposed into a thick non-porous layer of sludge material which
was detrimental to the growth of their plants.
Subsequently they had to re-work many plantings and incorporated a mix
of ¾ coarse bark and ¼ coarse sand or fine gravel. (In question period he also mentioned a mix of ¾ sand and ¼
bark.) An organic mulch is used over
the beds and no fertilizer is given to the alpine species. Steve contends that the alpine species are
not long lived and should be replaced in about 20 years and the soil renewed.
In
Steve’s presentation of dwarf rhododendrons, he included those of up to 3-4
feet tall but which are so slow growing they do not reach that height for many
years. The true dwarfs such as most of
the Lapponicums e.g. R. impeditum
grow on scree areas and require excellent drainage.
Steve’s
first picture was of the rare and difficult to grow R. ludlowii a very choice tiny plant with large (for the size of
plant) yellow flowers. In nature it grows
on wet, mossy rocks but Steve grows it in a trough. R. forrestii v. repens,
with large red bells, but often very
sparse flowering, creeps over rocks and can reach 12 feet or more
across.
His
next slides were the “not so dwarf” species including several with excellent
foliage and indumentum. Some of those
shown were R. haematodes, R. piercei, R. pachysanthum and R. roxeianum, all with brown or reddish
indumentum. R. pseudochrysanthum makes a neat dome and in some forms the new
leaves have a distinct white edge. R. camanulatum v. aeruginosum and R. pronum both have very bluish new
foliage but rarely bloom. R. proteoides, rare and much sought
after, makes a tight little dome with lovely foliate and reddish indumentum.
Some
of the delightful dwarfs were R.
ferrugineum, the Alpenrose, with small brick-red flowers, the newly
introduced R. tsaii (affinity); a
purple Lepidote, R. radicans, a
creeper with large purple flowers and the lovely R. campylogynum with plum-purple or pink ‘thimble’ bells held high. Some azaleas shown were the creeping R. nakaharae with salmon-red flowers, R. kiusianum in neat mounds covered in
small flowers and the taller R. canadense,
our native easterner which grows in boggy meadows.
Those species mentioned above are only a few of his numerous slides which were taken in the R.S.F garden. Many of the species shown are being propagated at the R.S.F. garden for sale now and in the next few years more will be added from species Steve has collected in the wild. Those members who managed to pick up a copy of the R.S.F. 2000 Plant Catalog that Steve brought to the meeting could salivate over the selection of species offered for sale.