The leaves are oval, 8–15 cm (3+1⁄4–6 in) long and 6–10 cm (2+1⁄4–4 in) broad, oblique at the base, acute or rounded at the apex, with a wavy-toothed or shallowly lobed margin, and a short petiole 6–10 mm long; they are dark green and thinly hairy above, and grey beneath with dense grey hairs.

The Latin term mollis means "soft", and refers to the felted leaves, which turn yellow in autumn.

The fruit is a hard woody capsule 12 mm (0.47 in) long, which splits explosively at the apex at maturity one year after pollination, ejecting the two shiny black seeds from the parent plant.

[2] H. mollis is widely grown as an ornamental plant, valued for the strongly-scented flowers appearing in winter when little else is growing.

[1][5] The cultivars 'Jermyns Gold'[6] and 'Wisley Supreme'[7] have gained the Royal Horticultural Society's Award of Garden Merit.