Lachnospermum umbellatum is a small, stiff shrublet with numerous upright stems arising from a woody base. The plant grows to about 600 mm tall. The stems are densely covered with tiny, succulent leaves grouped into star-shaped clusters. One side of each leaf is covered in pure white wool; the leaf edges are rolled over this wool, leaving a clean white stripe along each leaf.

Flowerheads are borne on short stalks at the tips of the branches in groups of up to twelve. The stalks all arise at the same point on the branch, producing a floral arrangement termed an umbel.

Flowerheads are small, less than 10 mm across, and each flowerhead consists of a tight grouping of up to twenty tiny pink flowers termed florets. The individual florets are not very visible except on close examination, and the main part of the floral display comes from the attractive series of bracts that surround each flowerhead. The bracts are white-woolly but have pink tips which are bent outwards.Flowering is in summer, from January to April, frequently in the first year after a fire.