Gardenia is a shrub, 0.3-3 meters tall; young branches are often covered with short hairs, the branches are cylindrical and gray. Leaves are opposite or in whorls of three, leathery, rarely papery, varying in shape, typically oblong-lanceolate, obovate-oblong, obovate, or elliptical, 3-25 cm long, 1.5-8 cm wide, apex acuminate, abruptly long-acuminate, or short-acute and blunt, base cuneate or short-acute, both surfaces usually hairless, upper surface bright green, lower surface darker; lateral veins 8-15 pairs, prominent beneath, flat above; petiole 0.2-1 cm long; stipules membranous.