Deciduous or semi-deciduous, glabrous shrub up to c. 2 m high, forming dense thickets; stems erect at first, arching to horizontal from second year; bark reddish and becoming papery, deep brown on older stems. Lvs spreading to ascending; petiole 3-10 mm long, narrowly winged, reddish, channelled above; blade lanceolate or narrowly elliptic to rhombic (especially on vegetative shoots), 30-75-(90) × 7-25-(30) mm, acute, narrowly cuneate at base, pale to dark green on both surfaces, with primary veins obvious and sometimes purplish, irregularly and deeply 1-2-serrate to lobed, especially in upper 1/2 of blade. Infls glabrous, spreading, compound corymbs terminating short lateral branches, up to 30-(40) mm wide and 20 mm long; peduncles up to 12 mm long. Sepals broadly triangular, 1-2 mm long, greenish. Petals suborbicular, 3-4 × 2-3 mm, white. Stamens < petals. Fr. of erect, glabrous, dark follicles.