Clematis is one of the most popular flowering vines, and no wonder -- this versatile plant can be grown on walls, pergolas, in containers or left to ramble through trees and shrubs.
There are more than 600 named varieties of clematis and many more seedlings.
Flower colors range from pinks to purples, blues, reds and whites and even a few yellows, with multicolored options as well.
With so many clematis plants to choose from, it is hard to know what to pick.
Clematis varieties are classified into three groups according to blooming time and characteristics:
• Group 1 (spring bloomers, which flower on old wood only).
• Group 2 (repeat bloomers, which flower on both old and new wood).
• Group 3 (summer or fall bloomers, which flower on new growth only).
Most varieties are deciduous, meaning their leaves drop in the fall; but there are a few evergreen clematis, including armandii and cartmanii, which belong to Group 1.
There is a lot of diversity among clematis flowers, with different varieties having different shapes, sizes, colors and forms. Flower shapes can resemble bells, lanterns, tulips, stars or saucers. Flower size can be no larger than an inch up to 8 inches across.
Some produce single blooms while others are doubles.
The flowers are definitely the showiest part of the plant, but many varieties have beautiful seed heads after bloom. While many clematis plants are vines, there are a few varieties that are nonclimbing and are grown as clump-forming perennials or small shrubs.
WARM HEADS, COOL FEET
When planting clematis, choose a site with full morning sun or filtered sun.
Most clematis, especially the summer-flowering ones, like bright light on their tops and a cool, rather moist area for their roots. To help keep the base of the plant and the roots cool and shaded, you can plant them where other plants can shade them, put a layer of mulch at the base, or plant the roots on the northern side of a trellis and pull the vine to the sunny side.
Although clematis will grow in full sun, the blooms fade quickly if it's strong afternoon sun. You will find the plants have more intense colors if given some protection from the hot afternoon sun -- but they will not flower well in the shade.
FRAGILE FEELERS
Clematis need a well-drained, neutral to slightly acidic soil. If yours is a strongly acidic soil, adding a little lime to the planting area will help.
Clematis vines are not too keen on having their root systems disturbed after planting. Don't plant a lot of seasonal color around them that causes you to dig things up every year. Clematis have feeder roots close to the surface.
Some gardeners plant them at the base of another shrub and let the vine grow within the other shrub for support -- and they bloom fine.
Fertilize as they begin growing using a well-balanced fertilizer. Repeat again a month later.
Clematis are not drought-tolerant, needing regular water through the growing season.
HELP THEM CLIMB
Clematis do not have tendrils to climb with but actually climb by twisting their leaf stalks around supports, so it is necessary to provide some form of support when growing them against walls and solid fences.
You can use a trellis or mesh for the clematis to twine around, but they often need a little assistance getting started on their support structure. Lightly attach the vine with a soft twist-tie. Clematis vines are not as flexible as many other vining plants, so use care not to break off a vine while getting it attached.
CUTTING REMARKS
Pruning is a concern for many gardeners, and not all clematis are pruned the same way.
If left unpruned, many clematis vines eventually appear dead at the base with woody, ungainly stems that produce all their flowers at the top of the vines. Some grow weaker, with fewer flowers each season, while other, more vigorous species start bearing a heavy flower display at the top of the plants and end up pulling themselves down under their own weight.
Proper pruning of clematis vines stimulates growth, which increases the number of flowers, and makes the plants more attractive.
Timing is critical and varies with the type of clematis you are growing.
• For Group 1, the spring-only bloomers, do whatever pruning is needed after they finish blooming.
• For Group 2, those that bloom on both old and new wood, you can remove dead or weak wood in the spring as new growth begins. Deadheading the spent blooms will keep them blooming freely.
• For Group 3, those that bloom on the new growth, prune fairly hard before new growth begins. Staggering the pruning heights can give you a fuller vine with flowers from top to bottom.
KNOW YOUR GROUP
If you do not know which group your clematis belongs to, let it grow for a year and time the flowering. If it blooms in the spring only, it is Group 1. If it blooms spring and intermittently all summer, it is Group 2; and if it doesn't start blooming until June or later it is Group 3.
There are hundreds of clematis plants to choose from, but if you are just getting started, some of the most commonly available clematis varieties are
• Group 1 -- white blooming, evergreen Armand clematis and pink "Apple Blossom," Clematis x cartmanii "Avalanche" and white Clematis montana Grandiflora.
• Group 2 -- "Henryii" with large white flowers and "Nelly Moser" with pink and white striped blooms.
• Group 3 -- "Ernest Markham" with magenta blooms and "Jackmanii" with purple flowers.
Sweet autumn clematis blooms in late summer to fall with hundreds of fragrant small white blooms, but it can become a bit too vigorous in the garden.
Check your local nurseries to see what they have available. Clematis vines can be addictive -- once you get started growing them, you will start to add more to your garden.
Janet B. Carson is a horticulture specialist for the University of Arkansas Cooperative Extension Service.
HomeStyle on 05/20/2017