Species In Our
This white-flowered Asian azalea is in Subgenus Pentanthera, Section Sciadorhodion. It is part of the distinct group of deciduous azaleas, which have whorled leaves. The specific name, ‘quinquefolium’, means ‘having five leaves’; the plant is also referred to as Cork Azalea, a name which comes from its gray-brown corky bark.
This graceful, compact plant with spectacular autumn color is slow growing as a young plant. It reaches 2-3 feet in cultivation and is a rather dainty shrub, wider than high. Its leaves unfurl in whorls of 5 on the tips of branches and are light green, often tinged along the edges with red. In the wild it can grow up to 15 feet in height. It grows in central Japan above 3000 feet in shady ravines. It forms great masses and intermingles with R. pentaphyllum, usually pink, with R. degronianum growing underneath.
The leaves, 2 inches long by l l/2 inches wide, are broadly elliptic with a hairy midrib above and below. The leaf petiole is very short and hairy; young branchlets are hairy, but become glabrous with age. The flowers are often 2 inches across, pure white with green spotting at the base and come in groups of two or three; they are bell-shaped and rather pendulous. The calyx is green and hairy. The flowers often are often partially hidden by the foliage.
Cox in The Larger Rhododendron Species states that R. quinquefolium is a tricky plant to grow in Scotland, but it does well in SE England. It does well in the Northeast, especially in semishade and with some wind protection. Greer says it is hardy to -5°F. Dr. Gustov Mehlquist grew it well in chilly Storrs, CT. though; that ought to encourage many more of us to try it. It has been known to be a favorite of rabbits.
Claire Smith, Belmont, MA