JARS v46n3 - Watts With the Species: R. auriculatum

Watts With the Species: R. auriculatum
Lynn Watts
Bellevue, Wash

Reprinted from the Seattle Chapter newsletter, April 1992

If you have room in your garden for only a few larger rhododendrons or even if you have room for only one, then you should seriously consider R. auriculatum . One of the latest to flower in the genus, R. auriculatum is an especially desirable plant. The sweetly fragrant blossoms which appear as late as August in the Seattle area are a most welcome sight. As an added bonus, the scarlet ribbon-like bracts of the newly emerging foliage provide an interesting contrast to the bright green leaves.
First discovered by Augustine Henry in western Hu-peh Province, China, in 1885, it was introduced into cultivation in 1901 by E. H. Wilson. In its native habitat, R. auriculatum is found at altitudes ranging up to 7,500 feet and between latitude 30 degrees north and 32 degrees north. Despite this relatively low altitude-latitude locale, it has proven remarkably hardy in the British Isles and in the Pacific Northwest. It is reputably hardy to -5 degrees Fahrenheit.
R. auriculatum is a tree-like, upright spreading rhododendron which will reach heights of 33 feet in the wild but is much more subdued in cultivation, seldom growing taller than 15 feet. The very distinctive 8-to 12-inch long leaves provide a sure identification of this species. On the upper surface of the leaf there are stipitate-glandular* hairs with spherical glands on the tips. The under surface of the leaf is a lighter green having scattered villous** hairs with no glands on the tips.
Flowers are fragrant, borne in clusters of 6 to 15, 7-lobed, funnel-shaped and creamy white to rosy pink with a greenish coloring in the throat. (I don't like the word "blotch." It has an unpleasant connotation that hints of a birth defect.) Flower buds of this rhododendron also help to provide quick identification. They are large, conical and tapered to a definite point with bracts or outer scales distinctively long and sharply tipped.
Our first R. auriculatum was purchased from J. Harold Clarke in 1976. It was then a 3-foot plant and has since grown to a height of 8 feet with a spread of 12 feet. It seems quite happy in its location and rewards us with a delightfully fragrant midsummer floral display. Because of its late flowering, usually in the warmer part of our summer, R. auriculatum should be planted in a location which will give some protection from the midday sun during its blooming period.

Editor's Note:
* Stipitate-glandular: hairs are borne on short stalks and bear glands.
** Villous: bearing long and short hairs.