Proper clematis care begins by planting the root ball 3 inches below the soil surface in a hole at least 12 inches deeper and wider than its root ball or nursery pot. After filling the hole with amended soil, apply a 2-inch mulch layer over the root zone to keep the roots cool, and keep the area moist, but not wet. Apply a liquid plant fertilizer monthly during the growing season except when the clematis is actively flowering.
Site selection is essential to proper clematis growth. In cooler climates, six hours of daily sunlight is sufficient, while in locations with hotter summers, partial afternoon shade keeps the plants cooler and inhibits premature fading of clematis blooms. Clematis vines require good air circulation to discourage mildew and other fungal diseases, as well as a trellis or other structure upon which the leaf stems, called petioles, can cling to as the clematis matures.
Proper clematis pruning ensures maximum flower production and a beautiful vine framework. Hard-prune the clematis vine its first year, cutting the vine back to 12 inches above the ground and leaving one pair of buds. In subsequent years, pruning techniques depend on whether the variety blooms on the previous season's growth or the new season's growth. Clematis cultivars that bloom on the previous season's growth are not pruned until after flowering, then pruned only to remove weak or dead stems. Some cultivars in this group bloom early, then again later in the season on new growth. These are shape-pruned in early spring by removing 12 inches from each shoot along with weak and dead stems. Clematis varieties that bloom on the new season's growth are pruned back to 3 feet in February or March, leaving only live canes with at least one pair of robust-looking buds on each stem.