With its profuse blooms and trailing habit, verbena adds striking color and texture to gardens and containers. This classic annual or perennial provides long-lasting color through heat and humidity. But when it comes to cold tolerance, verbena has its limits. Just how chilly can verbena withstand? Here’s what you need to know about growing verbena in cold climates.
Evaluating Verbena’s Cold Hardiness
Most verbena varieties grow best in warm conditions. They thrive in zones 9-11 where freezing weather is rare. Traditional verbena species tolerate temperatures down to the mid 30s F before incurring damage. But modern breeding has increased cold tolerance in some newer verbena varieties.
General cold tolerance guidelines for verbena include:
- Standard verbena handle temps to the low 30s F before damage occurs.
- Improved cold tolerant varieties can withstand temps down to the mid 20s F.
- Once temperatures dip below freezing, verbena sustains damage. Flowers and buds blacken and leaves die back.
- Brief light frosts are tolerated better than prolonged freezing temps which can be deadly.
- Verbena growing in garden beds may survive colder temperatures than container grown plants.
So while verbena prefers hot conditions strategic planting and care can stretch its growing range. Select cold hardy verbena varieties and provide winter protection in zones 7-8 to maximize performance.
Growing Verbena Successfully in Cold Climates
With the right verbena varieties and care, you can enjoy verbena in cooler zones. Follow these tips to help verbena thrive
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Choose verbena bred for cold tolerance like the Quartz XP and Imagination series. These withstand temperatures into the 20s F.
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Plant verbena after the last spring frost date to avoid damage to young plants.
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Give verbena transplants a head start over seedlings. Transplants mature quicker.
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Site verbena in sheltered microclimates protected from wind and receiving ample southern sun exposure.
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Cover verbena when frost threatens using fabric row covers. Remove covers during daytime.
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Ensure excellent drainage in garden beds and containers. Wet soil loses heat faster than dry soil.
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Apply 2-3 inches of mulch around verbena plants to insulate soil and roots from temperature extremes.
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Avoid high nitrogen fertilizer in fall that spurs tender new growth prone to winter damage.
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Prune leggy verbena growth in late summer to compact plants before winter.
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Bring container grown verbena plants indoors overnight on cold nights.
Managing Verbena Through the Winter
Verbena’s performance diminishes as temperatures drop. Flowering decreases and plants exhibit dieback. Here’s what to expect over winter:
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Annual verbena dies out under heavy frost. Only perennial types possess marginal winter hardiness.
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Lower leaves and stems die back first as cold damage progresses up from the roots.
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Plants may enter dormancy but remain alive underground. Protect crowns from freezing.
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In very mild climates, some winter flowering occurs but plants lack their full vigor.
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Evergreen verbena varieties like Quartz XP retain more leaves than trailing types but exhibit minimal growth through winter.
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Avoid cutting back verbena completely in fall. Leave 1-2” of stem to protect crowns and enable re-sprouting.
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Container verbena should be discarded after frost kills plants. Perennial verbena may re-emerge in spring.
Achieving the Longest Verbena Season Possible
While verbena won’t thrive through harsh winters, you can maximize the growing season in cooler zones. Choose cold tolerant varieties suited to your climate zone. Plant in protected microclimates. Cover plants when frost threatens. And remove covers to allow sunlight during winter warm spells. With a little extra care, you can enjoy vibrant verbena for many months, even in challenging climates.
When Temperatures Rise
As the mercury climbs, Verbena can start to sweat it out. Upper limits for these plants are less about a specific number and more about avoiding the scorching sun. If your Verbenas leaves look sunburned or growth halts, its time to provide some shade.
When the thermometer reads below 60°F (15°C), consider it a cold red flag for your Verbena. Frost is a definite no-go. If youre seeing browning stems or a general lack of enthusiasm, its a sign to warm things up. Remember, Verbena isnt a fan of the cold shoulder.
❄️ Cold Stress Symptoms
Conversely, Verbena sends clear distress signals when its too cold. Leaves might darken and turn mushy, like a forgotten fruit in the fridge. The plant may also have brown spots or droop, making it look like it’s giving up. Keep an eye out for these signs to ensure your Verbenas survival through temperature tantrums.
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FAQ
What is the lowest temperature lemon verbena can tolerate?
How hardy are verbenas?
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Can verbena withstand cold temperatures?
Here is a general overview of verbena’s ability to withstand cold temperatures: Most verbena varieties tolerate temperatures down to the mid to low 30s Fahrenheit. Some newer verbena varieties can tolerate temperatures into the mid to upper 20s Fahrenheit range. Once temperatures drop below freezing, verbena will suffer damage.
Which verbena plant is suitable for winter care?
Another type of verbena that is suitable for winter care is Verbena rigida. This plant is native to South American countries such as Brazil, Argentina, and Peru and is known for its upright growth habit and small, pink flowers. Verbena rigida is a hardy perennial, so it can handle cold temperatures and is well-suited to winter care.
Is Verbena cold-hardy?
Many varieties of verbena are not cold-hardy and will suffer from frost damage, so it’s important to select a variety that is better suited for your climate. Look for varieties such as Verbena bonariensis, Verbena hastata and Verbena rigida, which are all more tolerant of cold temperatures.
What happens if a verbena plant freezes?
Once temperatures drop below freezing, verbena will suffer damage. Flowers and buds will blacken. Leaves may turn mushy and die back. While verbena can withstand short periods of frost and freeze, prolonged exposure to freezing temperatures will kill the plant. Factors like location and weather conditions impact exact cold hardiness.
Can verbena be potted?
Unpotted verbena will likely be killed off by the first hard frost (when temperatures dip well under freezing). You can pot up in-ground verbena by digging up the entire plant. Here’s what to do: Cut the plant back to less than half its size. Carefully dig it up, then trim the roots in half.
How do you care for verbena x hybrida in winter?
To care for Verbena x hybrida in winter, it’s best to prune it back in the fall to encourage new growth in the spring. Additionally, it may be beneficial to apply a layer of mulch around the base of the plant in late fall to protect the roots from cold temperatures.