Lemon verbena (Aloysia triphylla) makes a cheery neighbor on your back yard with its fresh-green leaves that exude a light fragrance of lemon when you brush. This tropical indigenous thrives as a semi-evergreen perennial in U.S. Department of Agriculture plant hardiness zones 8 through 10. It may grow to 6 feet tall and spread 8 feet broad, and provides small lilac flowers on the summer season.
Pruning
Like many shrubs, lemon verbena gains from a pruning in spring or early summer to eliminate dead branches as well as other sun damage. At this time of year, you may use the clippings to root new plants. Lemon verbena reacts to pruning by creating fresh leaves at the whorl immediately under the cut instead of along the whole stem. Consequently, this tree may grow leggy. It takes regular pruning throughout the year to increase leaf production. Snip off leggy comes just above a leaf whorl.
Outdoor Planting
Lemon verbena requires well-draining dirt to thrive; “wet feet” will doom the plant sooner instead of later. It also needs at least six hours a day of sunlight. Generally it’s ideal to plant verbena in full sunlight, although just a tiny afternoon sun is helpful in warmer climates. Ideal growing conditions consist of loose soil rich in organic matter and tons of room to get the shrub’s spreading roots. Unlike many herbs, lemon verbena likes to be fed regularly, so plan to fertilize at least once a month during growing season.
Container Planting
As a perennial, lemon verbena develops a spreading root system. If you plant it into a pot, then you need to decide on a large one that is no less than a foot around to allow for root growth. The more dirt around the lemon verbena’s roots, the more it’s insulated from temperature fluctuations. Some gardeners bury the container in the soil for additional protection. If you choose this option, take care the plant’s roots do not find their way into the garden dirt, creating problems when the pot is moved. Container-grown lemon verbena ought to be fertilized every two weeks. If you transfer the plant inside for the winter, thin the plant before bringing it indoors to remove any spindly stems.
History
The Aloysia genus, named for Maria Luisa de Parma, wife of King Charles IV of Spain, includes at least 30 species of aromatic shrubs along with lemon verbena. Originally classified as Verbena triphylla, lemon verbena’s botanical name has been changed to Verbena citriodora because of its fragrance. It was moved to the Aloysia family when researchers noted that its fruit separated into two nutlets instead of the four that characterize the fruits of Verbena species. It’s still possible to find lemon verbena offered as “citriodora,” but decades ago it was renamed “triphylla” because of the whorls of three leaves that form over the stems.