It has been called “the queen of vines.” With its lush foliage and wide variation in flower colors and sizes, the clematis has easily earned that title and a spot in the garden.
Carol Newcomb enjoys sharing her love of clematis. As owner of Northland Rosarium, 9405 S. Williams Lane in southwest Spokane County, she carries about 50 varieties of these amazing vines and knows firsthand how rewarding it is to grow them.
“Clematis is a large, diverse group of plants that will grow from 12 inches up to 20 feet and comes in all sorts of different colors,” she said. “No matter what your space, there’s one that will fit it.”
While some might think they’d be challenging to grow, Newcomb says that’s not the case at all.
“They’re very easy vines to grow,” she explained. “It’s said they like their head in the sun and feet in the shade, which is very true. They like some sun – although will tolerate a lot of shade – and like their root system to stay cool.”
This can be accomplished by placing mulch over the root area and planting a perennial or rose at the base of the plant to shade it a bit.
Clematis can be planted throughout the garden season, although spring is considered best because it gives them the opportunity to become established well before fall. Most clematis are in USDA hardiness zones 3 and 4, so they thrive in the Inland Northwest’s climate.
“Since the plants can live up to 50 years, it’s important to get them off to a good start,” Newcomb advised. “They like a rich growing environment, plenty of water and they like to be fertilized.”
When selecting a location for a clematis vine, remember they will need to grow up on some type of support. Since they climb by wrapping their petioles, or leaf stalks, around a support, ones that are the diameter of a pencil work best. Newcomb suggests using cattle panels, fishing line or wire. Some gardeners grow clematis on a fencepost, arbor, or through a tree or rose. All of these methods add a vertical element to the landscape.
Plants should be fertilized twice during the growing season: in the spring when tidying up the garden and again in midseason. Newcomb suggests doing the second fertilization before the end of July, which gives plants a chance to use up the rest of the fertilizer before the fall. She advises against feeding them while the plants are flowering, however, as this can encourage green growth at the expense of blooms.
Newcomb recommends organic fertilizers, alfalfa meal and compost, or balanced fertilizers such as 20-20-20 or 10-10-10.
Knowing when to prune a clematis vine can be confusing. Most clematis have been divided into three main groups that identify bloom time and when to prune them. There are also herbaceous clematis, which die back to the ground every year.
Refer to the accompanying box for an explanation of each group and how to prune them.
Even so, Newcomb doesn’t want gardeners to be fearful of pruning their vines.
“You will never kill a clematis by pruning it wrong,” she said. “You’ll just change when they bloom.”