Ceanothus tomentosus, with the common names of Ramona lilac and woollyleaf ceanothus, is a species of shrub in the buckthorn family Rhamnaceae. It is native to several of the mountain ranges in California and Baja California.
C. tomentosus grows in dry, shrubby habitat such as chaparral. The habitat includes the Sierra Nevada and the Southern California Peninsular Ranges.
It is an erect shrub approaching three meters in maximum height. The woody parts are reddish, especially when new. The evergreen leaves are alternately arranged, oval in shape, dark green and slightly hairy on top and woolly on the undersides. They are edged with tiny glandular teeth. The inflorescence is a cluster several centimeters long of white to deep blue flowers. The fruit is a lobed capsule a few millimeters long which is sticky when new.