Rambler roses
Rambling roses produce vigorous growth and flower best on last season's stems. As a result, poor or no pruning will soon result in a mess of tangled stems bearing only a few flowers - so pruning to encourage the regeneration of new growth is essential for a good display.
The best time for pruning is in summer, once the single flush of flowers is over. Old overgrown bushes can also be tackled in autumn and winter. Begin by completely removing all dead, diseased, damaged and weak growth, taking out large stems in sections to minimise damage to the remaining stems. Then reduce the final framework to a maximum of six young, vigorous stems.
The remaining wood should then have all sideshoots reduced by two-thirds and the leader tip-pruned to encourage branching. A renovated plant will need feeding with a rose fertiliser and mulching with organic matter - such as garden compost - in spring. The resulting new growth should be tied in during the summer while it is still flexible.
Climbing roses
Neglected climbing roses sprawl with bare unproductive stems lower down and an entanglement at the top. The answer is to prune out most of the old wood aiming to promote a flush of new growth from the base. This task is best tackled during the autumn or winter months.
If necessary, remove the climber from its supports and lay it on the ground for better access. After pruning, spread the new stems over the supports and, if possible, bend the branches to a more horizontal position to encourage shoots from low stems and promote flowering.
With old, fragile climbing roses, excessively heavy pruning can be deleterious to the plant - sometimes new growth stubbornly refuses to sprout, and the rose will die. Limit the risk of this by spreading the work over several years, for example by removing up to one-third of older stems each season. This will ensure that there is always some young wood to sustain the remaining stems and roots. Application of a balanced fertiliser or proprietary rose food, mulching in spring and watering in dry weather will encourage growth and recovery.