Rose verbena (Glandularia canadensis formerly Verbena canadensis) is a hardy plant that with very little effort on your part, produces aromatic, rosy pink or purple blooms from late spring to late summer. Interested in growing rose verbena in your garden this year? Read on to learn how.
I. Appearance and Characteristics
Verbena canadensis (syn. Glandularia canadensis), commonly known as rose mock vervain, rose verbena, clump verbena or rose vervain is a perennial herbaceous flowering plant in the verbena family (Verbenaceae). It is native to the eastern and south-central areas of the United States. This species is widely cultivated as an ornamental, and naturalized populations have been established outside its native range, such as in the northeastern U.S.
V. canadensis is a perennial herb that grows low to the ground, typically to about 1 foot (30 cm) high. Roots will form where stems touch the ground, and over time the plant will spread to form a low mound. Leaves, up to 8 centimeters (3 in)long, are dark green on the upper surface and lighter green below. Leaves are semi-evergreen, opposite and pinnately-lobed. Flowers are pink to purple, and consist of a tubular corolla that opens up into 4 or 5 spreading lobes. Flowers bloom in the spring and can persist until fall. The plant attracts butterflies, rabbits, and deer.
II. How to Grow and Care
Light and Temperature
Ideally, verbena should be planted in full sun during spring or early summer after the last spring frost date if you live upstate or in the plateau regions.
If you live by the coast, fall is the ideal season.
A quick pinch to the tips of the plant will encourage thicker foliage.
They require full sun for proper growth.
The USDA hardiness zone for verbena is 9 through 10.
Watering and Feeding
Verbenas grow best if they are not watered from above. Using a soaker hose is an excellent option.
They will be alright if they receive around an inch’s worth of rain, but if not, they need to be watered at least once a week during their blooming phase.
Established plants are drought tolerant. However, expect slower growth and fewer blooms when plants experience dry spells for long periods.
Soil and Transplanting
Verbenas require well-drained soil.
They may suffer if they are grown on overcrowded soil with poor ventilation, shade or in too wet of soil.
In fact, if your verbena isn’t growing properly, the problems are most likely due to improper growing conditions.
Verbenas should initially be kept in moist soil until the roots have grown enough to spread to the surrounding soil.
At no point should the soil be too dry.
Although verbenas may survive drought to some extent, their growth is stunted and their appearance is affected over time.
Apply a thin layer of slow-release fertilizer in mid to late spring.
Repeat this if you’ve trimmed the plants to bring them back in bloom.
If the soil is too coarse and poor, you may need to fertilize a little more frequently.
A controlled-release fertilizer or liquid plant food is the best option.
Grooming and Maintenance
- If blooming is slow during the summer, trim around 1/4th of the plant, including both the height and width.
- Make sure to provide enough water and a bit of fertilizer.
- Within 2-3 weeks, it will be back in bloom.
- Dead-heading of faded verbenas is crucial to allow the rest to flourish.
- Give the verbena a light trim in the fall, but don’t go overboard since new growth begins in spring.
- Too much pruning will make the plant susceptible to destruction during a cold winter.
- They do not have a very long lifespan and may need to be replaced after 2-3 years.
Propagation
Propagate Verbena from seeds or cuttings.
To Propagate from Seed:
- Dead verbena flowers will leave behind a brown seed pod.
- Wait for it to dry out, then rub it to release the verbena seed.
- In the spring, spread out all your seeds over moist soil and leave them uncovered.
- Over time, they will start to germinate on their own.
To Propagate from Cuttings:
- Ideally, use summer cuttings for this process.
- Take a cutting which is at least 3″ inches tall and has no flowers.
- Remove all leaves except the top ones and place them in a pot of moist soil.
- After a few weeks, its roots will start to grow.
Pests and Diseases
This plant is susceptible to pests of which some are a mere annoyance while others could cause irreversible damage.
These pests include:
- Leafminers
- Aphids
- Mites
- Scale
- Mealy Bugs
- Whiteflies
- Gall Midgets
- Thrips
- Foliage-Feeding Caterpillars
Before going straight for an insecticide read the usage instructions to prevent damage to your plant.
Pests such as aphids or mealybugs are removed using a blast of water or removed with a cotton swab.
Another option is to introduce beneficial predators to your garden such as the praying mantis.
For serious infestations please consult your local gardening center for more details.
When it comes to diseases trailing verbena can have a few and these include:
- Botrytis Blight
- Powdery Mildew on plants
- Pythium Root Rot
With Botrytis Blight you’ll notice tan spots on the leaves or established plants rotting around the crown.
To manage Botrytis Blight maintain low humidity levels and improve air circulation around the plant.
Also, remove dead or dying flowers and leaves and to protect healthy plants apply a fungicide.
Powdery Mildew will show as white fungal growth on the surface of leaves or on flower petals.
Apply a fungicide to protect plants from powdery mildew.
For Pythium Root Rot you’ll have dark brown roots and plants will appear wilted and yellowed.
To avoid this do not over-water plants.
To manage the root rot pot in pasteurized media and keep hose ends off the ground.
Protect healthy plants by applying a fungicide.
III. Uses and Benefits
Verbena grown close together give a colorful, lively, blanketed effect.
Flowers in pink, purple and other colors cluster at the top which attracts butterflies.
They attract butterflies and may be grown in hanging baskets for another pop of color.
They create an attractive appearance in the landscape when grown in full sun window boxes, as a ground cover. Add color to rock gardens and beach landscapes and is one of our annuals for the beach.
