Ceanothus arboreus is a species of shrub endemic to California, especially to the Channel Islands. It is known commonly as feltleaf ceanothus. It is a species of what are sometimes called California lilacs, and may be referred to as the California mountain lilac or island mountain lilac. It is one of the tallest of the genus, growing up to 25-30 ft. in height, bearing glossy dark green leaves which are leathery or felt-like on their undersides. It is sometimes planted as a fast-growing ornamental for its showy bright blue flowers, which grow in plentiful panicles, or bunches, of tiny five-lobed blossoms. Some varieties and cultivars have light, powder blue blooms, and others bear darker blue flowers.