Melissa officinalis aka Lemon Balm

Melissa officinalis, or lemon balm, belongs to the mint family. Its native range runs from the Mediterranean to Central Asia. This perennial herb has escaped gardens across much of North America. It forms a bushy clump with many upright stems. Garden plants reach about 2–3 feet (0.6–0.9 metres) tall. They spread about 1.5–3 feet (0.45–0.9 metres) wide. Some reach 3.3 feet (1 metre) in both directions.

The green leaves grow in pairs along square stems. They have an oval or heart shape and rounded teeth. Their wrinkled surface feels rough and carries fine hairs. Leaves can reach 0.26 feet (0.08 metres) long. Their lemon scent makes them useful in the kitchen. Green stems can turn woody as they age. The plant sheds its leaves for winter. Small flowers grow where the upper leaves meet the stems. Each flower has two lips. Most are white, though cream or pale purple flowers occur. Bloom runs from May through August, with some flowering into fall. Bees visit the flowers, and the plant also draws butterflies. Its capsules produce many seeds that can grow into new plants.

Lemon balm grows in full sun or partial shade. Afternoon shade helps in places with hot summers. It accepts sandy, loamy, clay, and poor soils. It also grows across acid, neutral, and alkaline soil conditions. Good drainage matters more than rich soil. Keep it clear of excess winter wet. Established plants cope with drought, though moist soil also suits them. Sources place it in USDA zones 3–7 and UK hardiness class H7.

Use it in herb beds, border fronts, or informal ground cover. Containers help limit its spread from rhizomes and seed. Sources differ on how strongly it spreads. Some describe mild self-seeding; others warn of aggressive growth. Cutting back after bloom limits seed and brings fresh leaves. Deer tend to leave it alone. Serious pest and disease trouble is uncommon. Sage leafhopper may attack it. Powdery mildew, leaf spots, leaf blight, and gray mold can occur. Verticillium wilt occurs rarely.

Leaves and flowers can flavor tea, soups, and other foods. Eat leaves raw or cooked, or dry them for tea. Dried leaves also add scent to sachets and potpourri. The herb has a history of medicinal use. ASPCA lists it as non-toxic to cats, dogs, and horses. Concentrated preparations may cause irritation, especially on sensitive skin. PFAF also advises avoiding medicinal use during pregnancy.