A. nepalensis is a large deciduous alder with silver-gray bark that reaches up to 30 m in height and 60 cm in diameter. The leaves are alternate, simple, shallowly toothed, with prominent veins parallel to each other, 7–16 cm long and 5–10 cm broad. The flowers are catkins, with the male and female flowers separate but produced on the same tree. The male flowers are 10 to 25 cm (4 to 10 in) long and pendulous, while the female flowers are erect, 1 to 2 cm (0.4 to 0.8 in), with up to eight together in axillary racemes.[1] Unusually for an alder, they are produced in the autumn, with the seeds maturing the following year.