How to Cultivate Clematis
Add dimension, spectacular flowers and year-round interest to your garden by choosing one of the most popular vines today — clematis. The captivating vine produces beauty that truly speaks for itself.
"I encourage people to grow the summer-growing clematis because they're the easiest ones to care for," says clematis expert Maurice Horn.
Clematis produces flowers on new growth, last year's growth, or both, depending on the species. You can maximize your flower-power by how and when you prune.
"My friends in England cut it back by half in early June to force new terminals so they can get new blooms," says Horn. In Oregon's mild temperatures, however, the plant is setting plenty of terminal buds without pruning. "I have this plant blooming on and on throughout the season with a fairly good flush of blooms," Horn adds.
Broken or damaged stems can of course by cleaned up, but before you prune aggressively, know the particular requirements for the particular cultivars you've planted.
The one time when all clematis needs to be pruned is just before planting. Cutting back before planting stimulates root growth and promotes new growth for a lot of stems.
Planting and Caring for Clematis
Horn selects 'Negritianka' because of its very dark bloom. He removes the garden tape from the stake for easier access to the stems and makes a cut just above a leaf axil. Next, he mixes lots of organic compost — at least 2 inches' worth — with the native soil. Into the planting hole the plant goes, along with a stake or trellis.
He then covers the plant with soil so that it's positioned deeper than it was in the pot. He ties the stems back to the stake loosely, and then waters thoroughly.
"Those of you that live in Northern climates can plant clematis deeper than I would normally plant them here in the Pacific Northwest, which is a very mild climate," says Horn.
Clematis prefer to keep their roots cool, so Horn recommends shading them with another plant. Horn notes that clematis also likes to ramble through shrubs and trees. "I like to use clematis types that don't have much volume, like these double-flowered forms, with rhododendrons," Horn says. Rhododendrons are evergreen, but they lose their interest quickly after the spring, and with the combination of the clematis, these two plants will blossom from spring into summer.
Combining with other plants is just one example of how this wildly versatile plant can be used in the landscape, especially, when you consider that many, like this clematis. The species Integrifolia, which is hardy in USDA Zone 3, do well in some of the colder parts of the country. "Most of the large-flowered hybrids that I've shown you are hardy down to Zone 5, and a few are hardy down to Zone 3," Horn days.
So if you're clamoring for clematis, check what's available in your local nursery or garden center for a good indication of which plants will grow in your area. When purchasing clematis, find established plants with lots of stems.