The Desert Willow is an upright shrub or small tree that grows to a height of 25 feet. The trunk grows up to 6 inches in diameter and has dark brown, scaly bark. Narrow, alternate, light-green leaves are 3 to 6 inches long with very pointed ends. Slender brown twigs are often hairy or sticky.

The Desert Willow is not a member of the Willow Family (Saliaceae) as are true willows, but is the only species of the Bigonia Family (Bigoniaceae) native to California. This deciduous plant is classed as a phreatophyte, and is an indicator that water is not too far below the surface during part of the year.

The common Spanish name Mimbre means willow-like, referring to the long, slender leaves. The wood of the Desert Willow is used for fenceposts. A tea is sometimes made from the dried flowers and seed pods.