Lemon Verbena Plant Profile

Lemon Verbena Plants in the Garden

soniabonet / Getty Images 

When it comes to lemon-scented herbs, lemon verbena has the most intense concentration of oils per square inch of plant material. Devoid of bitterness, this plant is beloved as an additive to drinks, baked goods, or anywhere you might use lemon zest. The spear-shaped leaves of lemon verbena grow quickly in hot summer weather, replenishing the plant as you harvest throughout the growing season. For those who live where lemon verbena is hardy, the plant can become an anchoring shrub in your landscape, ready to release its citrusy aroma whenever you brush by.

Botanical Name Aloysia citriodora
Common Name Lemon verbena, lemon beebrush, vervain
Plant Type Tender perennial in frost-free zones
Mature Size 6 feet where hardy
Sun Exposure Full sun
Soil Type Rich and moist
Soil pH Slightly acidic; 6.1 to 7.0
Bloom Time Late summer
Flower Color Purple buds open to white blossoms
Hardiness Zones USDA growing zones 8 through 11
Native Area South America, especially Chile and Peru
Lemon Verbena Leaves
 Luis Echeverri Urrea/Getty Images
Lemon Verbena Patio Plant
Courtesy Missouri Botanical Garden PlantFinder
Lemon Verbena Leaves and Tea
Geo-grafika/Getty Images 

How to Grow Lemon Verbena

The fragrance and size of lemon verbena plants make them a valuable addition to the back of the sunny herb border. Set your plants out at the same time you plant tomatoes, coleus, and other warm weather lovers. A site with full sun, rich soil, and regular moisture will result in quick growth for the harvest.

Light

Lemon verbena needs full sun, similar to what roses or a vegetable garden would need. Situate your lemon verbena plants where they won't be cast in the shade of a neighboring tree or building. Plants that grow indoors as houseplants may need supplemental artificial lighting to prevent lanky growth and leaf drop.

Soil

Lemon verbena does well in rich garden loam, but average soil is also tolerated. Good drainage is important for healthy lemon verbena plants, so in areas with clay you must plant them in raised beds or containers.

Water

Lemon verbena needs regular irrigation. A lack of water leads to plant stress, leaf drop, and insect pest infestation. Keep the surface of the soil moist, but don't oversaturate the plants. Aim for a moisture level that resembles that of a wrung-out sponge. An exception is plants spending the winter months indoors: they may be kept on the dry side.

Temperature and Humidity

In its native South America, lemon verbena plants grow in a sunny, frost-free climate. Temperatures below 40 degrees Fahrenheit will trigger leaf drop and dormancy. Plants do well in dry or humid climates.

Fertilizer

Lemon verbena is a departure from other herbs in that it appreciates a regular fertilizing schedule to keep it lush and vigorous. Feed plants in the spring with an all-purpose fertilizer. Watering each time with compost or manure tea during the growing season will keep plants productive.

Potting and Repotting

Pot up your lemon verbena in rich potting soil. Amend the soil with leaf mold or composted manure to ensure a healthy start. Potted plants moving indoors for the winter will lose many leaves. Repot plants in the spring before new growth begins.

Propagating Lemon Verbena

Lemon verbena is propagated in the same way as other woody herbs like rosemary and lavender, by taking semi-ripe cuttings. Snip a flower-free stem above a leaf node. Remove all but the top two set of leaves, and insert the cutting into moist, sterile potting mix. Keep moist until new leaves begin to form. Transplant into a sunny site with good drainage.

Toxicity of Lemon Verbena

According to the ASPCA, lemon verbena is mildly toxic to dogs, cats, and horses, causing stomach upset and colic. The small amounts that one would use in cooking do not present a problem, but ingestion of the concentrated oil causes toxic effects.

Pruning

Lemon verbena plants growing in containers rarely exceed two or three feet in height, but outdoors in frost-free climates the shrubs can exceed eight feet. Over time, the shrubs can get woody and lanky. Cut plants back by half in early spring to encourage compact, bushier growth.

Harvesting

You can harvest the leathery leaves of lemon verbena anytime for recipes. Because the leaves are tough, you must mince them finely if you plan to consume them. You can also infuse sauce, oil, sugar or tea with whole leaves. The tiny blossoms of lemon verbena also carry its heady scent, and can be used in the same way as the leaves.

Growing in Containers

Growing lemon verbena in a container is an ideal way to cultivate the plant all year in colder regions, Container-grown lemon verbena also stays a more manageable size than plants grown in the ground. Choose a potting soil enriched with time-release fertilizer to give plants a head start. Keep the container in full sun, and water daily. Bring your plant indoors or to a greenhouse when temperatures drop below 40 degrees Fahrenheit.

Growing From Seeds

Lemon verbena flowers produce few viable seeds. Those that are produced rarely germinate, and therefore gardeners should start with young lemon verbena plants rather than seeds.

Common Pests/Diseases

Lemon verbena growing outdoors in full sun and rich soil is rarely plagued by pests. When brought indoors to overwinter, spider mites and whiteflies seem to be drawn to the plants as they struggle to acclimate to weaker light and less humidity. Mist plants frequently to disrupt the dry conditions that spider mites enjoy. Put out yellow sticky traps if whiteflies congregate.

Lemon Verbena vs Lemon Balm

Lemon balm (Melissa officinalis) and lemon verbena have similar uses in the kitchen. Lemon balm is a hardy perennial, and will return in the landscape each year in zones 3-7. As a member of the mint family, lemon balm spreads vigorously, and can become invasive. On the plus side, it is more shade tolerant than lemon verbena. You can distinguish lemon balm from lemon verbena by its rounded, wrinkled leaves on low growing plants. Although both plants have a strong lemon scent and flavor, lemon balm has a somewhat astringent tone whereas lemon verbena is more floral.

Lemon Balm
Lemon Balm. Courtesy Missouri Botanical Garden PlantFinder