6 Tips for Growing Clematis – the Queen of Climbers
Clematis can play an important role in any flower garden. As they scramble up trellises, climb over arbors and thread themselves through other plants, these perennial vines weave a living tapestry of color and texture. Read on for six tips that will help you be successful growing clematis, a plant that deserves its title “the queen of climbers.”
Know the Options Before You Buy
There are hundreds of clematis varieties to choose from, and they vary in height, bloom time, flower form and color. You’ll find compact cultivars that grow just 3-feet tall, and others that can reach heights of 20-feet or more. Flowering times can be late spring, summer or fall. There are even re-blooming clematis that flower twice per season, in summer and again in early fall.
Flower styles also vary. While most clematis have large, star-like flowers with 6 or more petals, there are also frilly doubles, delicate miniatures and even varieties with lovely bell-shaped blossoms. And then there’s color! Flower colors for clematis include white, pink, red, burgundy, lavender, purple and even yellow.
Once you see all the options, you will probably find it difficult to settle on just one clematis. So don’t! Consider planting two different varieties side by side. Combining an early-blooming and late-blooming clematis will keep you in flowers for months.
Be Aware of How Clematis Climb
Vines climb in several different ways. Some have twining stems (like beans and morning glories) or tendrils (like wisteria and sweet peas). Others have adhesive pads (ivy) or clinging stem roots (climbing hydrangeas). Clematis climb by using the stems of their leaves, which they are able to coil like a tendril.
It’s important to understand how clematis climb, because their twining leaf stems are relatively short. When choosing a trellis, keep in mind that the stems can’t wrap around anything that’s more than 1/2″ thick. Thinner is better, and a wire grid is usually the best option. Consider using woven or welded wire animal fencing that has a 1″ or larger grid. If you prefer the look of a traditional trellis made from wood slats or steel bands, attach a wire grid over the surface to support the vines.
Choose a Good Planting Location
Clematis are long-lived plants and do not like to be moved. Consider the planting site carefully with the goal of giving your new clematis a permanent home. The ideal location should have fertile, well drained soil with a loose, loamy texture.
To maximize flower production, site your clematis in full sun. Though most varieties will grow in half-day sun, they do not produce as many blooms. Clematis that are known to perform relatively well in half-day sun include Jackmanii, Nelly Moser and Henryi.
If possible, choose a spot where the plant’s root zone will be shaded and stay relatively cool. If there are no plants nearby to shade the soil, you can mulch around the base of the plant with shredded leaves or compost. Keep the mulch a few inches away from the plant’s stems.
Here are a few places to consider planting clematis:
- Against a wall (although not under a roof overhang that would block rainfall)
- 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 or tuteur
- Around a lamp post or mailbox (attach wire mesh)
- In a container (compact varieties)
Take Care When Planting
The root system of a clematis is wiry rather than fibrous. This is one of the reasons why a two-year-old clematis plant has a considerably smaller root ball than than other two-year-old perennials. You’ll also find that the vines themselves are relatively brittle and need to be handled gently.
When you’re ready to plant, loosen the soil to a depth of about 12.” Add compost and mix well. Dig a small hole and position the new plant so the crown (where roots meet stem) is positioned about 2” below the soil surface. Backfill the hole and water deeply to settle the roots. Water regularly during the first growing season to ensure the roots don’t dry out. Your clematis may need a full year to get established before it begins producing flowers.
Protect the young plant from nibbling mice, rabbits and voles by surrounding it with a cylinder of wire mesh. Even though it will take a couple years for the plant to reach its full height, the vines need support right from the start.
Provide Proper Support
Though some types of clematis have a bushy growth habit, most are born to climb. And as with other climbing plants, the new shoots need to find something to grab onto or they will stop growing and die back. Providing your clematis with right type of support will help it look good and grow well.
It’s common to underestimate how tall the trellis needs to be. If it’s too short, your clematis will reach the top and then flop over on itself. This is not a great look, and any breaks in the vine will make it more susceptible to disease.
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 can be made into a strong and attractive trellis that lasts for many years.
A newly planted clematis should be given a “training” trellis to help it get started. You’ll need 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.
If you want to keep your clematis looking tidy, keep an eye out for wandering vines — especially during May and June. Tie them in regularly, while they are still young and supple.
Keep Pruning Simple
Each clematis variety falls into one of three pruning groups, based on where the vine sets its flower buds. This determines how the plant should be pruned. Many gardeners already find pruning intimidating — even without having to keep track of which variety needs which technique. Here is a simpler approach.
If your clematis sends up most of its new growth from the base of the plant each spring, you can be quite sure it flowers on current year vines. For best results, simply cut the entire vine to a height of 12-18″ (do this in early spring rather than fall).
If your clematis produces most of its new growth on last year’s vines, it should be minimally pruned — only enough to remove dead or week stems and maintain the desired shape. The best time to prune these plants is late summer, right after they flower.
If you are curious about the various pruning types and how to care for them, you’ll find everything you need to know on the website of the International Clematis Society: Pruning Clematis.
Keep in mind that you probably won’t need to do any pruning at all for the first two years after planting. This will give you time to watch how your new clematis grows, so you can prune accordingly.
Should your clematis ever outgrow its allocated space, know that you can start anew by simply cutting back the entire plant (in early spring) to a height of 6″. Stray vines may be trimmed back any time during the growing season.