LET’S TALK ABOUT clematis (kle-MA-tis); or maybe you’d rather discuss clematis (KLEM-a-tis) — it’s complicated, right? Career nurseryman and longtime Great Plant Picks adviser Alex LaVilla is here to help us crack the clematis code.
Before we get into the vagaries of classification, pruning and other tangled directives, LaVilla advises gardeners looking to grow clematis to think like nature. “It’s a vine,” he says. “It’s meant to grow in companionship with other plants.” Which is how LaVilla cultivates the many clematis he tends in his typically sized, passionately planted back garden.
Clematis are long-lived perennial vines that scamper, climb, drape and tumble. The plant family is vast, but I’ll stick to varieties found at your local nursery or mail order specialist. LaVilla credits clematis expert Maurice Horn, co-owner of Joy Creek Nursery (joycreek.com) and fellow GPP adviser, with much of his success with clematis.
With the right choices, you can have clematis blooms from early spring through fall. But a quick glance at most clematis plant tags, with references to Group 1, 2 or 3 and attendant pruning directions, sends most of us scrambling for reference books. The following ABCs are an easy way to simply and successfully introduce the “queen of climbers” into your garden.
A — Alpine, anemone and evergreen (armandii) clematis produce small blooms on large vines in early spring. Provide plenty of space and a sturdy support structure; prune to tidy after blooming.
B — These varieties are a bit of a bother, but then most great beauties are. Group 2 clematis produce large blooms on both old and new wood for a display that continues for most of the summer. However, selective pruning and sorting through old and new stems is like unpicking a tangled skein of yarn. This group is also subject to the dreaded clematis wilt, a fungal disease that causes vines to summarily whither. It can kill a plant back to its roots, which means all that unpicking was for naught.
C — Cultivate success. Group 3 clematis include a number of beautiful, sturdy and resilient vines that bloom on growth produced in the current growing season. Flowering begins in midsummer and often continues into fall. This group includes plants in the viticella and texensis groups, as well as a number of lovely Japanese hybrids with lantern-shaped blooms.
In his garden, LaVilla focuses on the latter group, threading vines up and through established woody shrubs to provide both armature and color contrast to the flowers. Pro tip: Rather than cutting the plants all the way to the ground, in late winter LaVilla prunes them back to where he wants them to begin blooming in the coming months. “[The plants] get a good start in the sun, and you don’t have to reinvent a support structure year after year,” he says.
Also in group 3, Clematis integrifolia are shorter plants with a non-vining habit that die completely to the ground each winter, making them suitable for growing with other herbaceous perennials.
When planting, LaVilla recommends siting clematis close but not immediately beneath shrubs to avoid root competition while the vine is getting established. Place a slim bamboo pole to direct new growth to its woody host. Clematis appreciate a cool root zone, but contrary to what many references say, LaVilla advises Pacific Northwest gardeners to not plant clematis any deeper than the plant was growing in its nursery container. Provide regular summer water and fertilize in early spring and again in summer with an organic rose and flower formula.