Clematis have an important role to play in any flower garden. As they scramble up trellises, climb over arbors and thread themselves through other plants, these perennial vines weave a rich tapestry of color and texture. Read on for six tips that will help you be successful growing the “queen of climbers.”
Do Your Research
There are many wonderful clematis varieties to choose from, with lots of variations in height, bloom time, flower form and color. Compact cultivars grow just 3-feet tall, while others can reach 20-feet or more. Flowering times can be late spring, summer or fall, with re-blooming types flowering both early and late in the season.
Flower styles also vary. There are big, star-like singles, frilly doubles, delicate miniatures and even lovely bell-shaped blossoms. And then there’s color! Flower colors include white, pink, red, burgundy, lavender, deep purple and even yellow.
With so many options, you can probably find several different clematis for various places around your yard and garden. If you have the room, consider planting two different varieties side by side. Combining an early-blooming and late-blooming clematis will give you months of flowers.
Understand How They Climb
Vines climb in several different ways. Some have twining stems (like morning glories) or tendrils (like sweet peas). Others have adhesive pads (ivy) or clinging stem roots (climbing hydrangeas). Clematis use the stems of their leaves, which they can coil like the tendrils of a pea vine.
It’s important to know how clematis climb, because their twining leaf stems are relatively short. When choosing a trellis, keep in mind that these plants can’t grab onto anything that’s more than about 1/4″ thick.
Choose a Good Planting Location
Clematis are long-lived, and they don’t like to be moved, so consider the planting site carefully. The ideal location will have well drained soil that’s rich and loamy.
If possible, find a spot where the roots will stay relatively cool. In most cases, you can count on nearby plants to shade the soil. If the planting area is more open, plan to mulch the soil surface with shredded leaves or compost, keeping the mulch a few inches away from the plant’s stems.
To maximize flower production, plant your clematis in full sun. Though most varieties will grow in half-day sun, they won’t produce as many blooms. Some varieties that tolerate half-day sun include Jackmanii, Nelly Moser and Henryi.
Here are a few places to consider planting these colorful vines:
- Against a wall (although not under an overhang where it won’t get any rain)
- On a fence (attach wire mesh if needed)
- Near a shrub or small tree (for easy support)
- With another vine (such as a climbing rose)
- Over an arbor or pergola (attach wire mesh if needed)
- Along the top of a stone wall
- On a free-standing trellis
- Around a lamp post or mailbox (attach wire mesh)
- In a container
Take Care When Planting
You’ll probably notice that the root system of a clematis is wiry rather than fibrous. This is one reason why a two-year-old clematis plant is smaller than most other perennials. The vines are also relatively brittle and need to be handled gently.
When you’re ready to plant, dig a generous hole, add compost and mix well. Position the crown of the plant (where the roots meet the stem) about 2” below the soil surface. Backfill the hole and water deeply to settle the roots. Water regularly during the first growing season. You can expect your plant to spend the first year getting established and start blooming year two.
Surrounding the young plant with a cylinder of wire mesh will help protect it from nibbling mice, rabbits, and voles. Even though the plant won’t reach its full height the first year, it’s important to provide a trellis, right from the start.
Provide Proper Support
There are some types of clematis that have a bushy growth habit, but most are born to climb. As with other climbing plants, new shoots are always searching for something to grab onto. If the vine can’t find anything to attach itself to, the new shoots stop growing and die back. Providing the right type of support will help your plant look good and grow well.
Clematis vines need to be handled with care. Older stems appear to be woody but will crack if they’re bent. Young stems look supple but are actually quite brittle. This makes it difficult to rescue a plant that starts to flop midseason.
To avoid heartbreak, give your clematis a trellis that’s large enough to provide good support. And make time in late spring and early summer to corral wandering stems and tie-in top-heavy growth.
One of the simplest and most effective trellises for a clematis is a wire grid with openings that are 2” to 4” in diameter. Black or green poly-coated fencing is strong and long-lasting. If it’s flexible, you can even mold it around a post or along the top of a fence. Concrete reinforcing wire (sometimes called re-mesh) is rigid and more challenging to handle, but it makes a great trellis and will last for many years.
Give your young clematis a “training” trellis to help it get started. Cut a 12″ square of chicken wire or some other relatively flexible wire mesh that has 1″ or 2″ openings. Anchor this mini trellis to the ground behind the plant and then attach it securely to the permanent trellis.
Keep Pruning Simple
Each clematis variety falls into one of three pruning groups, which specifies how the plant should be pruned. If you’re like most gardeners, you already find pruning intimidating — even without having to keep track of which technique is right for which variety. So here is an easier approach.
If your clematis sends up most of its new growth from the base of the plant, you know that it will flower on current year vines. These plants can simply be cut back each year in early spring, to a height of 12-18”.
For clematis that produce most of their new growth on last year’s vines, limit your pruning to maintaining the desired shape and removing dead or weak stems. The best time to prune these plants is late summer, right after they bloom.
Bear in mind that you won’t need to do any pruning for the first year or two, so you’ll have time to see how the plant grows and can then prune accordingly.
Should your clematis ever outgrow its allocated space, you can simply cut back the entire plant to a height of 6″. This can be done in fall or in early spring. Stray vines may also be trimmed back any time during the growing season.