I have a clematis on an obelisk and all the leaves are brown. Do I remove those and cut down the clematis? If so, how much should I leave, or should it be cut back to 4 inches above ground?

A clematis can look quite brown and dead after a long winter. It is tempting to cut it back to the base, along with other perennials that benefit from this tidying up. However, the clematis is the poor man’s pruning minefield. The key is knowing when your clematis blooms, for that determines the “when,” the “what,” and “how much” to prune. Spring-flowering clematis (April-May) flower on their old wood (previous season’s growth). Pruning before flowering removes their blooms. Once flowering is finished, old stems can be cut back in early summer, enabling new growth to ripen the rest of the season for next spring. Clematis alpina, Clematis macropetala and Clematis montana fall into this first category.

The second clematis group flower on short stems produced on last season’s old wood. These are the early large-flowered hybrids, the double and semi-double flowers, and the mid-season hybrids which flower by the end of June. Pruning is essentially light. Remove dead, broken or weakened stems. Watch out you don’t remove a vine at the plant base that has flowering buds higher up. Varieties in this group are ‘Miss Bateman,’ the well-known ‘Nelly Moser,’ ‘Duchess of Edinburgh,’ and ‘General Sikorski.’

The third clematis group only flower late in the season, well after mid-June and into autumn. They only flower on new wood. Pruning involves cutting back all the previous year’s growth to just above a good pair of buds, about 10 to 12 inches above ground. Don’t prune this type of clematis any earlier than the end of February or beginning of March. Hybrids in this category are ‘Jackmanii,’ and the Clematis viticella cultivars.

Knowing when your clematis blooms is the key to making an informed pruning plan.