7 Care Tips For Overwintering Your Clematis This Season
Are you preparing your flowering clematis plant for winter this season, but aren't sure where to start? These perennial vines are a garden mainstay, but can be susceptible to frost. In this article, gardening expert Liessa Bowen shares her top tips for overwintering your clematis this season.
Clematis is a group of over 250 species of flowering vines. Most clematis varieties are climbers that grow well on a trellis, fence, or other structural support frame. There are species that can be grown from climate zones 3 through 9 and bloom in the spring and summer months, some even blooming into early fall.
These beautiful flowering vines are popular for good reason. Clematis flowers are often large, showy, and quite colorful. These popular vines commonly bloom in purple and shades of white or pink. There are also numerous bicolor varieties.
Some varieties sport small fragrant flowers, while others bloom with an abundance or large single or double flowers. Some varieties are evergreen, while others lose their leaves each winter.
Many varieties of Clematis will grow well in cold and moderate climates, while others prefer warmer climates. Make sure the varieties you choose are tolerant of your climate zone. But what do you need to do to prepare your Clematis for the winter months? With a little winter preparation and annual maintenance, you can keep your plants healthy and blooming year after year.
Add a thick layer, approximately 4-6 inches deep, of mulch around your Clematis. Spread the mulch to a 2-foot radius around the base of the plant. This will help insulate the roots and protect them from harsh winter weather.
A hearty layer of mulch helps the soil around the roots retain moisture, even in the winter, when the plant isn’t actively growing. A layer of mulch or compost will also help the roots retain moisture throughout the rest of the year.
For mulching, you can use well-aged compost, hay, wood chips, bark chips, or leaves. You can combine mulches as well. For example, put a layer of rich, organic compost around the plant, then top that with a layer of wood chips or hay for a mulch that’s rich in nutrients, protective, and insulating against extreme winter weather.
Clematis likes to be kept moist, but not saturated or soggy. Even after blooming has ended, continue to water your plants until they die back naturally. If you are growing Clematis in a container, continue to water regularly to keep the roots moist. Check your potted plants frequently, as plants growing in containers will dry out faster than those growing in the ground.
If you experience a particularly dry winter, you may need to water your Clematis, even if it’s dormant. Similarly, if a particularly cold frost is expected, you can help protect your plant’s roots by giving it a drink of water before the heavy frost.
The water acts as a protective layer which can help insulate against a damaging freeze-defrost cycle. Again, water until the soil is moist, but not saturated.
Clematis are classified into three groups, based on their blooming periods. Some groups require pruning, while others do not. You should first identify which group your Clematis belongs to so you know if and when you will need to prune.
If you don’t know which group you have, you may need to observe your plant for a year or two and see when and where it blooms.
If you do need to do some pruning, be sure to use sharp pruning shears. When pruning, be sure to leave several feet of base vine, from which new growth will emerge. Also be sure to prune during the correct season, so your plant has time to grow and bloom according to it’s seasonal schedule.
Group 1: Early Spring Bloomers
- Blooms in early spring or even late winter.
- Produces flower buds on old wood, from last year’s vine.
- Requires no pruning, other than basic maintenance.
- Plants in this group often grow a thick woody base stem.
- This group tends to be less cold hardy and therefore better for warm climates.
Group 2: Repeat Bloomers
- Blooms heavily in spring.
- May have second smaller flush of blooms in summer.
- Produces flower buds on both new and old wood.
- Do some light pruning in early spring before first blooms.
- Do heavier pruning in summer after second blooms.
- This group tends to do well in moderate to warm climates.
Group 3: Summer or Fall Bloomers
- Blooms in late spring, summer, and into early fall.
- Produces flower buds only on new wood.
- Perform heavy pruning in winter before spring growth begins.
- Many in this group do well in cooler and moderate climates.
Sometime in late fall or early winter, you can deadhead your Clematis vine. Using sharp pruners, remove spent blooms and any dead or damaged vines. This keeps your plants looking their best.
Deadheading isn’t necessary, however, and plants will continue to grow and bloom regardless of whether or not you remove spent flower heads, so this is ultimately personal preference.
Fall and early winter is a great time to work with your Clematis vines to get them ready for another year of growth and flowering. Remove any dead vines and dead plant debris from around the plant that may host overwintering insect pests.
When the leaves fall and the plant goes dormant, it’s a good time to have a close look at your vines. This is a good opportunity to train your vines on a support system and untangle any vines that may have grown off in rogue directions. You can use small ties to secure your plant to a support structure, such as a trellis, arbor, or fence.
Winter weather can be harsh and unpredictable. Clematis vines are fairly hardy within their climate zone tolerance, but they can still benefit from a little extra protection when outdoor weather gets rough.
You can help protect the roots from extreme cold temperatures and repeated freeze-thaw cycles. Use a generous layer of mulch around the base of the plant, as mentioned above.
Be sure to help protect your plant from heavy winds. A strong wind can blow over a trellis that isn’t well secured. If you have vines growing on a trellis or other support, be sure that the plants are securely attached to the support, and that the support is secure and stable. You don’t want your entire plant falling over.
A heavy snowfall or thick coating of ice can add a lot of weight to a plant and it’s structural support system. Check on your plants during severe weather to be sure they are safe and well-supported.
Once the danger of extreme winter weather has passed, you can start to prepare your plant for the spring growing season. Remove extra thick mulch layers. Add a layer of nutritious compost around the base of the plant to give it some extra energy for blooming.
If you moved your potted plant to a more protected area for the winter, you can move it back into its summer location.
Extra Protection for Containers
If your plant is growing in a pot or other container during the winter, it may need a little more attention than an established plant growing in the ground. Clematis can successfully overwinter in a container as long as they are cold-hardy for your climate zone.
If you live in an area that is particularly cold, windy, or snowy, you can easily move a container-grown plant to a protected area, such as against a wall or surrounded by other shrubbery as a wind-break.
As with an in-ground plant, mulch around the base of the stem, covering the entire container surface with 4 to 6 inches of mulch. If you live in a place with solid freezes, give your potted plant an extra layer of protection. Wrap the pot with burlap or even bubble wrap, or you can pack evergreen branches or straw around the pot to offer extra insulation against repeated freezing and thawing cycles.
Also, be sure to check the soil moisture occasionally. Even in the winter, your plant will benefit from moist soil. Potted plants will dry quickly, especially in cold dry winter air. If your plant’s soil has dried completely, give it a mid-winter drink.
Clematis are hardy ornamental vines that bloom prolifically. Remember these steps to prepare your plant for winter weather, and also prepare it for the next growing and flowering season. With the right care and preparation, your Clematis will weather the elements in stride and burst into full bloom the following year!