How to Plant, Grow, and Care for Lemon Verbena
The lemon verbena plant is a lovely and elegant shrub. Learn to grow this perennial with Ann McCarron's complete lemon verbena growing guide.
Contents
The lemon verbena plant is by far my favorite herb to grow! It has the most aromatic, supercharged zingy lemon scent of all the herbs. Close your eyes, inhale and you’re instantly transported to a sun-drenched lemon grove in the Mediterranean, feeling uplifted, refreshed, and awake.
The leaves are used to infuse flavor into foods. Add a few fresh leaves to boiled water to make a revitalizing herbal tea. Use fresh leaves as a scented garnish in cocktails, cold drinks, and desserts. Infuse leaves in creams and butter to flavor ice cream, biscuits, and cakes. Also use as an alternative to a lemon zest rub to give a lemon zing to meat dishes. This is a herb with almost limitless possibilities.
As a perennial shrub, leaves are available all year but the best are from late spring to early fall making them even more valuable. Lemon verbena dries extremely well and retains its lemon flavor and scent to give you that warm Mediterranean vibe throughout winter.
Overview
Plant Type
Perennial shrub
Family
Verbenaceae
Genus
Aloysia
Species
Aloysia citrodora
|
Native Area
Argentina Northwest, Bolivia, Paraguay
Exposure
Full sun
Height
2-10′
Watering Requirements
Moderate
|
Pests & Diseases
Spider mites, aphids, whiteflies, pythium root rot
Maintenance
Low
Soil Type
Well-draining, moderately fertile
Hardiness Zone
8-10
|
What is Lemon Verbena?
Aloysia citrodora, commonly known as lemon verbena, is the superstar of the lemon-scented herb world. Other common names include lemon bee bush, cidron, and herb Louisa after the plant’s namesake, Maria Louisa of Parma, Queen of Spain.
Native Area
Lemon verbena originates from the dry rocky soils of South America, Argentina, Bolivia, and Paraguay. It is nowadays a common plant all over the world and is particularly favored in France and Spain for its citrus flavor. The shrubs grow well in a subtropical biome.
Characteristics
Lemon verbena is a woody tender perennial shrub, growing to eight feet wide and tall in optimal conditions. Plants are evergreen perennials in their natural tropical habitat, however, leaves will drop with the onset of cooler temperatures in northern climates.
The narrow leaves are bright green, lance-shaped, and slightly rough in texture. They grow opposite and whorled around woody stems. Like other members in the Verbenaceae family of plants, lemon verbena flowers develop as tall panicles of tiny pinkish-white flowers.
In the fall, leaves begin to brown at the edges, falling with the onset of frost resulting in a shockingly bare, spindly-looking shrub. Equally unnerving to the dramatic leaf loss is the fact that lemon verbena plants can be slow to come back to life in spring in cooler climates with often no signs of new growth until late spring or early summer.
Don’t give up on your plants too soon! Many lemon verbena plants have been discarded when they weren’t dead, simply snoozing.
Lemon verbena is not to be confused with herbs such as lemon balm. Lemon balm also has a strong lemon scent, but it is more astringent than sweet and leaves are rounder and wrinkled. It is also a very hardy perennial herb surviving below-freezing temperatures that would kill lemon verbena.
Uses
The powerful almost sweet lemon sherbet aroma and flavor from lemon verbena is increasingly sought after in the culinary and cosmetic industries. Leaves are used to flavor liquors, cakes, biscuits, sugar, and tea to name just a few things. The essential oil from lemon verbena leaves has excellent moisturizing and antiseptic properties making it a beneficial ingredient in skin creams and lotions.
Planting
For new home gardeners, it is best to start with a well-established shop-bought plant as lemon verbena can be tricky to propagate. Plant outside after the last frost has passed and with the onset of consistently warm weather. Lemon verbena can be sensitive to temperature changes so choose a sheltered location in full sun with moisture retentive well-draining soil.
This plant can be grown outside in cold climates, but add a deep dry winter mulch such as woodchip, bark, or straw to protect the roots from severe frosts. Alternatively, plant into a container filled with good-quality loam-based compost. Bring containers inside over winter.
When planting lemon verbena, ensure the planting hole or container is large enough for the root ball. Place the plant into the hole, keeping the base of the stem at the same level as it was in the pot. If stems are planted too deep, they may rot.
When it comes to spacing, consider the climate you live in and how you intend to use the plant. In hot climates, they will need room to grow. Plants grown for regular harvesting can be spaced 12-30 inches apart and should be kept in shape with regular trimming. Growing lemon verbena in a container will limit the plant height to around two to three feet tall.
How to Grow
Although lemon verbena is one of the more temperamental and tricky herbs to grow, it is well worth the effort when you get it right.
Light
Lemon verbena prefers lots of sun and heat over cool temperatures and shade. It needs a full sun position to maximize the essential oil and lemon scent in its leaves. Shade produces weak, spindly growth, so grow lemon verbena where plants receive a minimum of six hours of direct sunlight per day.
Water
Lemon verbena responds well to regular watering but should never be allowed to sit in constantly wet, heavy soil. Water plants using soaker hoses or by hand with water directed at the soil level. Prolonged drought will also trigger leaf drop, plant stress, and pest infestation. Check soil moisture content during periods of hot weather, especially plants grown in containers.
Watering is not necessary over winter for plants growing outside. Reduce watering for those brought indoors over winter.
Soil
A well-drained, moisture-retentive, moderately fertile soil is ideal for growing lemon verbena. Soil pH ideally should range between neutral to slightly acidic. Add loam-based compost to container plants to add a nutrient boost.
Temperature
Lemon verbena requires consistent temperatures above 50°F (10°C), to stimulate growth. In northern zones, plants may remain dormant until early summer when temperatures are consistently warm. Temperatures below 40°F (4°C) will trigger leaf drop and winter dormancy.
Grow lemon verbena in USDA zones 8-10. In colder climates, grow lemon verbena indoors in containers over winter and provide outdoor plants with a deep dry mulch to protect roots from frost.
Fertilizing
Fertilize lemon verbena every few weeks during the growing season with nitrogen-rich liquid fertilizer to encourage new healthy growth. Feeding will keep the plant producing new fresh leaves. A mulch of compost or a worm tea or compost tea now and then will boost it as well.
Maintenance
Lemon verbena plants can become sprawling and woody over time. Regular trimming of young leaves and stems will help keep plants productive. But after a while, branches may become spindly and congested. All lemon verbena plants benefit from a good rejuvenation prune, cutting branches back by a third in early spring to encourage compact, bushy growth.
Propagation
Lemon verbena is difficult to propagate from seed. Reliable seed sources can be difficult to find and saved seeds produced in cooler climates are not always viable.
The best way to propagate lemon verbena is via softwood or semi-ripe cuttings similar to other woody herbs such as rosemary and thyme.
Cuttings
Take softwood cuttings in spring, snipping four to six inches of new growth, removing the lower leaves, and placing the stems into pots filled with a 50:50 mix of compost and perlite or horticultural grit. Keep the cuttings moist and humid until roots form.
Softwood cuttings can be placed in a glass of water, which allows you to observe root development closely. Make sure to change the water every few days. When roots are well established, plant up individual cuttings into a larger pot and grow until well established.
In colder climates, it’s best to keep young plants undercover for a while longer and harden them off to outside conditions. Semi-ripe cuttings can be taken in late summer/early fall and should be kept indoors until spring the following year.
Harvesting
Lemon verbena leaves are excellent when used fresh. They are also easy to dry and retain their signature sherbet lemony scent for longer than many other herbs.
Fresh young leaves have the best lemon flavor. Leaves are ready to harvest when plants are well established and at least ten to twelve inches high. Pick a few leaves when needed if making a fresh herbal tea. For larger harvests cut stems back four to six inches to encourage bushy growth.
Storage
Store fresh stems and leaves in the refrigerator wrapped in damp kitchen paper or place stems into a glass of water until needed. Leaves dry quickly when bunches of stems are hung up or laid out on a flat surface in a cool, ventilated dark place. Crumble dried leaves and store them in an airtight container for one to two years.
Common Problems
Lemon verbena can be tricky to grow (especially in cooler climates) and requires patience and resilience to get the conditions right. The key is not to give up, because once you’ve harvested the zingy, fizzy lemon sherbet leaves you’ll never want to be without it!
Growing Problems
Getting the soil right and protecting plants over winter are the main issues experienced when growing lemon verbena. Aim for rich, well-drained soil that retains moisture.
Heavy wet soils will cause soggy roots to rot or freeze over winter. A thick dry mulch like straw, wood chip, or bark will protect roots and prevent soils from becoming waterlogged.
Ensuring plants have adequate direct sun is also essential for healthy plant development.
Pests
Spider mite adults are reddish-brown, live in large colonies on the underside of leaves, and thrive in hot, dry environments. You will know if you have spider mites if you see a fine webbing between leaves and stems. Plants show signs of decline as leaves turn yellow and drop off.
Start by blasting your plants with a strong stream of water. Insecticidal soap or neem oil can help if that doesn’t work. Unfortunately, spider mites tend to be resistant to most pesticide products on the market, so it’s important to rotate products until you find one that is effective. Stronger methods such as pyrethrin can also be used.
Aphids and whiteflies may also be an issue. If you notice tiny soft-bodied insects congregating on your plant, or white moth-like creatures flying around the plant when it is disturbed, use a strong stream of water from a hose to blast them off. Neem or insecticidal soap is a good follow up if necessary.
Diseases
Pythium root rot is a fungi that persists in poorly drained, wet soils or soils that are over-irrigated or have experienced prolonged heavy rainfall. Symptoms are presented as stunted growth, wilting, and plant death.
To avoid pythium root rot, plant lemon verbena in well-drained fertile soils and water consistently to keep the soil moist and not wet. Soil solarization is a good non-chemical treatment for affected soils or areas can be treated with an appropriate fungicide. Always check the label and follow instructions.
Frequently Asked Questions
Does lemon verbena come back every year?
Lemon verbena is a tender woody perennial that comes back every year in colder climates and will remain green in subtropical zones.
Is lemon verbena invasive?
In warm, tropical climates, plants can become quite large and may need regular pruning, but they are not invasive plants.
Can lemon verbena survive winter?
Lemon verbena requires winter protection. Grow lemon verbena in soil with good drainage and protect roots from frost with a thick dry mulch. Container-grown plants should be brought indoors over winter.