Ceanothus fendleri (Fendler['s] ceanothus, Fendler['s] buckbrush, deer brier[1]) is a species of flowering shrub native to northern Mexico, Arizona, New Mexico, west Texas and the northeastern Texas panhandle, Utah, Colorado, eastern Wyoming, and western South Dakota.

The stems and twigs are grayish green when young, reddish brown when mature, armed with spines up to 2.5 cm (0.98 in) long.

[2] The flowers are about 2 mm across[4] and white, borne in thick clusters emanating from the leaf axils,[2] particularly on the older stems.

[2] The fruits are three-celled capsules,[5] pink and glossy, forming an approximate rounded equilateral triangle with the stem at the center.

[2] The caterpillars of Erynnis pacuvius, the buckthorn duskywing, feed on this plant and other species of Ceanothus.