Kelways Guide to Clematis Pruning
(Alpina, montana, macropetala, montana, armandi.)These spring and winter-flowering clematis flower on the previous season's wood only need to be pruned if they have outgrown their space. If you wish to just tidy the plant or reduce the size, do so immediately after flowering. An older plant with woody stems is best pruned half one year and half the next to avoid losing it.
(Early Large flowered hybrids flowering May-June). Cut out all dead and weak stems in February or March. Start at the top and work down each stem until you find plump, healthy buds, and prune to just above these. If you cut lower down, you will be cutting off the next flowers.
If the clematis has outgrown its space or looks unbalanced, with a large tangle at the top, prune back by at least half its height after the first flush of flowers.
(Later flowering hybrids, viticellas, herbaceous types). This is the easiest category for beginners to tackle. In February or March, start at the bottom of each plant and work upwards to find the second pair of live buds. Prune to just above these.
Hard-pruned clematis are useful for growing through trees and shrubs that also require pruning at this time of year. If grown this way, the clematis top-growth may look untidy over the winter. If so, prune the top half of the stems to reduce the mass and then finish pruning in the usual way in February or March.