It’s important to site clematis in the right spot; these vines prefer their heads in the sun and their feet in the shade (roots stop growing when soil temperature reaches 25ºC). Keep roots cool by shading with a groundcover of annuals, or by mulching around the base of the plant. An eastern exposure will also protect plants from the afternoon sun, especially when placed against a sunny wall or other permanent structure. On smooth surfaces, provide latticework or other support to help vines climb. Vertical structures such as arbours and archways are also good growing sites. Planted beside small trees and shrubs such as Laburnum, lilacs and antique roses, clematis can extend the season by blooming after the flowers of the woody plants have faded.
In all parts of the country, clematis can be planted in mid- to late spring (after the frost is out of the ground) or in early autumn (four to six weeks before the first hard frost is expected, which will allow enough time for roots to establish). Select a strong, healthy plant with multiple stems growing from its base.
Dig deep, plant deep
1. Dig a hole 40 by 40 centimetres (if your soil contains clay, score the base and sides of the hole with a garden fork to make it easier for the roots to penetrate the surrounding soil). Add 10 centimetres of compost or well-rotted manure to the bottom and mix in well. Backfill with equal parts good-quality topsoil and compost or moistened peat moss, along with two handfuls of bonemeal.
2. Submerge the pot of clematis in water for two to three minutes before carefully removing the plant from the container. Gently tease out the tips of the roots at the bottom, but leave the main root ball intact. Position the clematis in the hole so that it sits about six centimetres deeper than it was in its container; this induces the plant to establish a basal root crown of dormant buds below the soil’s surface. These subterranean buds are an insurance policy: they will spring into action if top growth is damaged or the plant succumbs to clematis wilt (large-flowered cultivars are most susceptible).