flannelbush, (Fremontodendron californicum), shrub of the hibiscus, or mallow, family (Malvaceae), native to southwestern North America. The lower leaf surfaces have a felty texture. The shrub grows up to 5 metres (16 feet) tall and bears alternate, lobed leaves about 2.5 cm (1 inch) long. The handsome, yellow, solitary flowers are about 5 cm (2 inches) across.