Renovating overgrown climbers and wall shrubs
You can cut back climbers and wall shrubs quite drastically, and some will respond to this method. Others respond better to a gradually renovation.
Some climbers and wall shrubs tolerate drastic pruning and can be cut down to approximately 30cm (12in) from ground level. This drastic pruning means that flowering will take several years to resume, but allows new green shoots arising from the base to be trained into a new and rejuvenated framework.
Examples of plants that re-grow well from drastic pruning include: Abelia, Acacia, Ampelopsis, Aristolochia, Azara, Campsis, Celastrus, Cissus, Clematis, Cotoneaster, Hedera (ivy), Osmanthus, Pyracantha, Ribes sanguineum, Rosa, Vitis and Wisteria.
Some plants, such as Chimonanthus, Jasminum, Lonicera (honeysuckle), Parthenocissus and Polygonum (Russian vine) do better when renovated slightly less hard, cutting back to 60cm (2ft) from the base.
Cutting back to a framework
Some climbers and wall shrubs respond better when cut back to a main framework of branches, rather than to near ground level. Cutting to a bud or branch helps ensure that re-growth will be successful.
Examples of plants that respond well to this method include Actinidia, Billardiera, Bougainvillea, Callistemon, Escallonia and Passiflora (passion flower).
Other plants are better renovated gradually, cutting them back over two or three years. Each year, cut back one in three of the main stems to ground level, reducing the rest to half their length.
Examples of plants that prefer gradual renovation include: Chaenomeles, Forsythia, Garrya, Hydrangea, Magnolia and Schizophragma.