Lemon basil has narrow, elongated oval leaves that measure an average of 5 centimeters long. The square-shaped leaf stalks can grow anywhere from 20 to 40 centimeters tall with leaves growing opposite each other in pairs. The light green leaves are delicate with smooth edges and offer a light citrus aroma. During the late summer months, the plant will produce lemon-scented, white flowers on long light green bracts. Lemon basil has a very mild anise flavor with strong notes of lemon.