Lemon Verbena Vs. Lemon Balm

Hardiness

• Lemon balm is a hardy, herbaceous perennial, surviving winter's cold through U.S. Department of Agriculture hardiness zone 4. Lemon verbena is a tender, woody shrub that is only reliably hardy through USDA hardiness zone 8.

Growth Habit

• Lemon verbena is a sprawling, woody shrub-like plant, growing about 3 feet high in cultivation. It can be grown in a pot in areas where winters are severe. Cut all of its branches back to about 12 inches high and remove its leaves for overwintering indoors.

  Lemon balm is a herbaceous perennial that grows about 18 inches high and spreads 18 to 24 inches wide. It is very easy to grow and produces white to pinkish flowers in mid- to late summer. The flowers are prolific producers of seeds. Lemon balm will reseed itself in your garden unless you harvest the leaves before the flowers form seeds. Or cut the plant back right after it finishes blooming.

Botanical Characteristics

• Lemon verbena has long, smooth, light to medium green, shiny leaves that emerge in opposite pairs along the semi-woody stems of this multibranched plant. The tiny, light lavender flowers are borne along spiky panicles at the terminal end of the branches.

  Lemon balm has heart-shaped, slightly crinkled leaves with serrated edges. A member of the mint family, lemon balm has the family's characteristic square, hollow stems and leaves that form in opposite pairs. The tiny flowers emerge from the leaf axils all along the stems. Encourage your lemon balm to branch out by pinching the growing tips until midsummer, each time the branches grow to have three to four sets of leaves.

Cultivation

• Grow lemon verbena in fertile, relatively moist soil in full sun. It is commonly grown as a disposable annual plant, or in a container that can be brought indoors for winter. Ensure the soil doesn't dry out during its dormant period indoors in winter, but do not water it until the soil is dry about an inch below the surface. When the days lengthen in spring, bring it into bright light and begin regular feeding and watering.

  Like most herbs, lemon balm prefers well-drained soil of average fertility. It will not survive in soils that hold their moisture or never completely dry out. Lemon balm will grow most vigorously in full sun; in partial shade it will grow reasonably well, but will tend to be a little leggy and produce fewer flowers.