The Verbena genus contains more than 250 species of perennial and annual plants. The pure species are not commonly grown except by fairly specialized gardeners. Most of the Verbenas widely used as bedding plants or low trailers in containers are named cultivars derived from hybrid crosses of various native verbena species. You often will see these labeled as "Verbena x hybrida", "Verbena x" or "annual verbena" to distinguish them from the native species forms.
Hybrid annual verbenas are constant bloomers that are often potted or used as garden bedding plants, planted in masses, or as front edging plants where the sprawling habit is put to good use.
As annuals, these plants are generally planted in spring, as soon as all danger of frost has passed. Like most annuals, they are fast-growing and achieve full size within a few weeks.
|Botanical Name||Verbena x|
|Common Names||Verbena, annual verbena|
|Plant Type||Herbaceous perennial, usually grown as an annual|
|Mature Size||Up to 12 inches tall, 18-inch spread (depends on variety)|
|Sun Exposure||Full sun|
|Soil Type||Dry to medium moisture, well-drained soil|
|Soil pH||5.8 to 7.2 (acidic)|
|Bloom Time||Spring to fall|
|Flower Color||White, red, purple, pink, peach (depends on variety)|
|Hardiness Zones||9 to 11 (USDA)|
|Native Area||Cultivated hybrid; parent species mostly native to Europe|
These hybrid verbenas may perform as hardy perennials in zones 9 to 11, but they are more commonly grown as annuals in all zones. They are usually low-growing, trailing plants with dark green leaves and clusters of colorful flowers that bloom continuously from spring to fall.
Hybrid annual verbenas are best grown in relatively dry soil in a sunny location. There is very little care necessary, other than regular watering.
Plant verbena in full sun. Flowering will be much reduced in shady locations. This is a plant that requires eight to 10 hours of sun daily.
These plants like fairly dry soil with an acidic pH. Verbena is not particular about soil, except that it must be well-draining. Heavy clay will lead to root rot, so dig in several shovelfuls of compost or leaf mold to lighten your soil.
Keep plants evenly moist until established. Once mature, these plants have average water needs, but will readily tolerate short periods of drought. Many of the parent species of these hybrids are native to Mediterranean regions or dry prairies, and their water needs resemble the conditions of those regions.
Temperature and Humidity
Planted as annuals hybrid verbenas perform suitably in virtually any climate, but may decline in the hottest period of the summer.
Verbenas are not heavy feeders, but they do appreciate a monthly application of balanced, slow-release flower fertilizer to help them keep up the flower show, which can last from spring until frost.
Verbena vs. Lemon Verbena
There is often confusion when it comes to verbena and another plant called lemon verbena. Lemon verbena is a member of a different genus within the Verbenaceae and classified as Aloysia triphylla. Lemon verbena, which is grown mostly for medical purposes, has a scent whereas most verbena plants do not.
The various varieties of hybrid verbena are usually identified by their unique flower colors. There are notable selections:
- 'Lanai Royal Purple with Eye' (Verbena x hybrida 'Lanai Royal Purple with Eye' is a cultivar with bright purple flowers and contrasting white eyes.
- 'Texas Rose' (Verbena x hybrida ‘Texas Rose’) is a cultivar that bears reddish-pink flowers.
- 'Blue Princess' (Verbena x hybrida ‘Blue Princess’) is a newer hybrid variety of verbena that produces beautiful deep blue flowers.
- Superbina’" series is bred to resist powdery mildew and it sometimes becomes a short-lived perennial as far north as zone 7. Flowers are white or shades of lavender.
In addition to the Verbena hybrids that are so common as annual bedding and container plants, there are a number of pure Verbena species that you can try as garden perennials, though finding them can be a challenge. These species are welcome in the butterfly garden. Tall varieties belong in the cottage garden, naturalized meadow, or back of the border.
Many of these plants are more upright in growth habit and may look quite different from the hybrid trailers.
- V. hastata (blue vervain) is a North American native that grows to 6 feet tall with purplish-blue flowers. It is hardy in zones 3 to 8.
- V. bonariensis is a native of Brazil that grows to 4 feet with lavender flowers. It is hardy in zones 7 to 11. It is sometimes known as purple-top vervain.
- Glandularia canadensis was once considered a member of the verbena genus but has now been recategorized. The 'Greystone Daphne' cultivar has lavender-pink flowers and grows to 8 inches with a sprawling habit. It is hardy in zones 5 to 8.
- V. tenuisecta (moss verbena) has delicate, lace-like foliage and grows to 5 or 6 inches. They bloom during late summer and early fall and are hardy in zones 7 to 9.
Verbenas are so inexpensive as nursery seedlings that gardeners rarely feel the need to propagate them. You can, however, take stem cuttings and root them in a gritty seed-starter mix. Here's how:
- Take 3-inch stem cuttings.
- Strip off the lower leaves
- Plant them in seed starter mix.
- Moisten the soil.
- Place the pot in a sealed plastic bag to hold in moisture.
- After a few weeks, you should see new growth starting, indicating that the cutting has rooted and can be transplanted into the garden or a larger container.
How to Grow Verbena From Seed
Though normally planted from nursery seedling packs, verbenas are easy to grow from purchased seeds. These plants often self-seed in the garden, and the volunteers will "grow true" to the parent plants. Here are the easy instructions:
- Soak the seeds in lukewarm water for 24 hours prior to planting.
- Plant the seeds in starter trays filled with a peat-based potting mix, pressing the seeds lightly into the mix.
- Sprinkle peat moss over the seeds.
- Cover the tray with newspaper or plastic with ventilation holes punched in it (the seeds need darkness to germinate).
- Uncover the tray when the seedlings sprout and transplant them into their garden location.
Potting and Repotting Verbena
Verbena is commonly found in hanging baskets with a mix of flowers, where they make good "spillers" trailing over the sides of its container. For container planting, use any general-purpose peat-based potting mix, in a well-draining container. You can also pot verbena growing in the ground for overwintering.
Potted verbena can be overwintered. Unpotted verbena will likely be killed off by the first hard frost (when temperatures dip well under freezing) unless you pot it by digging up the plant by its root ball. Here's what to do:
- If potting, cut back the plant to less than half of its size.
- After digging it up, trim roots by half, as well.
- Find a container that leaves a couple of inches around the root ball and fill with potting soil.
- Put the newly potted plant, or the plant already in a container, in a sunny spot.
- Spray with a mist of water for the first few weeks indoors.
- Before the last frost and before you will bring it outdoors again, prune to encourage growth.
- Take the container outdoors or replant in the soil early spring or after the last hard frost.
Common Pests & Diseases
These plants are susceptible to powdery mildew, and they may be visited by common insect pests that can be treated with insecticidal soaps or chemical sprays. Such problems are rarely fatal to the plants, however.
Verbena is both a deer- and rabbit-resistant plant, so take advantage of this by planting it at the edge of your property where animals frequently browse.