An evergreen shrub 8 to 10 ft high with erect or arching branches. Leaves crowded on the stems, elliptic to oblong-ovate, 1 to 3 or 4 in. long and about half as wide, rounded at the apex. Flowers yellow, up to 3 in. across, borne singly on the ends of side-shoots as in D. rigida but on shorter pedicels.
Native of California, found there only on the islands of Santa Cruz and Santa Rosa; first described in 1873 but not introduced to cultivation in the U.S.A. until 1933, after which it gradually became known to Californian gardeners (E. K. Balls in Gard. Chron., 7th May 1960). Not in cultivation in the British Isles, so far as is known.
var. rhamnoides (Greene) Munz D. rhamnoides Greene; D. arborea Greene – Leaves pale glaucous-green, less crowded on the shoot than in the type, and up to 5 in. long, sharply tapered at the apex. This variety, like the type, is insular in distribution but found farther south, on Santa Catalina and San Clemente islands, which lie off the Californian coast south of Los Angeles. It was introduced to cultivation in Britain in 1963 by F. P. Knight, Director of the Royal Horticultural Society’s Gardens at Wisley, who received seed from the Rancho Santa Ana Botanic Garden early that year (Journ. R.H.S., Vol. 90, pp. 480-1).
It is too early to judge this new introduction. It has survived three mild winters out-of-doors on a wall at the Savill Gardens but Mr Findlay tells us that it has so far proved less free-flowering than D. rigida.