Melissa officinalis. Lemon Balm is an upright, tender perennial that grows to about two feet. Its stems are hairy and branching. The leaves are 2"-3" long, oval or heart shaped, deeply wrinkled and have scalloped edges. Flowers are white to light blue and occur in whorls around the leave axils. Leaves are opposite each other on square stems, like most members of the mint family. Excellent companion and bee plant. Refreshing tea from the leaves. Effective against herpes. Perennial.