Clematis are happiest when their roots are kept cool and moist, so try to plant them where the base of the plants will be lightly shaded by other, lower-growing species. Otherwise, use a clematis root protector, or top-dress the rootball (avoiding the immediate crown), with a generous layer of shingle or pebbles. In early spring cut back the previous year's stems to remove dead and damaged stems before growth begins. Then, cut all remaining stems back to where strong buds are visible. Apply a slow-release balanced fertiliser and a mulch of well-rotted garden compost around the plant - again avoiding the immediate crown.