A shrub up to 8 ft or more high; young shoots more or less hairy. Leaves ovate or oval, broadly wedge-shaped or almost rounded at the base, slender-pointed, finely toothed, 21⁄2 to 4 in. long, 11⁄4 to 21⁄4 in. wide on the barren shoots; those of the flowering twigs mostly 1 to 2 in. long; upper surface set with sparse minute hairs, the lower one thickly covered with appressed pale, stiff hairs giving it a dull grey hue; stalk 1⁄12 to 1⁄2 in. long, bristly. Flowers white, fragrant, about 1 in. across, produced five to nine (usually seven) together on downy racemes about 2 in. long, at the end of leafy shoots of about the same length. Petals roundish; style about the average length of the stamens, glabrous, divided quite half-way down; disk glabrous. Calyx and flower-stalk shaggy, like the undersurface of the leaves. Fruits top-shaped, 3⁄8 in. long.
Native of W. Hupeh and Shensi, China; discovered by Henry about 1887 and introduced by Wilson in 1904. It flowers late – from middle to late July or even into August – and the species is desirable on that account. It is also charmingly fragrant with an odour like that of hawthorn.
P. subcanus Koehne P. wilsonii Koehne; P. subcanus var. wilsonii (Koehne) Rehd. – This species is very closely allied to P. incanus and was first separated from it in 1904. It differs in having the calyx and the underside of the leaves more sparsely hairy; also the disk and the lower part of the style are downy (glabrous in P. incanus). Native of W. Szechwan. Wilson may have introduced it while collecting for Messrs Veitch, but it is mainly and perhaps wholly represented in cultivation by Wilson’s introduction during his first expedition for the Arnold Arboretum. The plants (sometimes labelled P. wilsonii) flower earlier than P. incanus, in late June or early July.
At Wakehurst Place in Sussex there are plants of unknown origin, the largest 15 ft high and as much wide, which agree with P. subcanus except that the style and disk is glabrous, as in P. incanus. The best is very free flowering, with racemes of up to eleven flowers, usually the lower two pairs in the axils of normal leaves.