Spyridium montanum is an erect shrub that typically grows to a height of , its young stems densely covered with white and rust-coloured hairs. Its leaves are elliptic or egg-shaped, long and wide on a petiole long. The edges of the leaves turn down and the upper surface is densely hairy. The flowers are white or cream-coloured and borne in groups of 10 or more wide. The floral tube is long; the sepals long and both are covered with white, star-shaped hairs. Flowering occurs from April to July and in October.
