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How to prune grapevines and wisteria in winter

Wisteria on Cotswold stone wall, Broadway, Worcestershire  - Neale Clark
Wisteria on Cotswold stone wall, Broadway, Worcestershire - Neale Clark

A couple of the garden’s monster annual pruning jobs hove into view in December, and it is time to get out our sturdiest ladders and sharpest pruning instruments and set to. Grapevines and wisterias produce little but jungle if left to their own devices. Each needs a regime to keep it in check and to encourage it to prioritise fruit (and flowers) above growth.

Short, ripened, gnarly growth leads to flower buds and fruit; long, whippy vegetative growth does not. Winter is the time to tip this balance in our favour. 

Prune grapevines now or soon: their sap starts to rise early in the new year and after Christmas they may “bleed” from the pruning wounds, which weakens the plant and splashes sap all over the patio. Vines that are grown along walls or fences are generally trained as cordons: one or two main stems are allowed to develop, and each stem’s side branches are kept shortened, to a few buds. Gnarly and productive fruiting spurs form on these side branches.

Pruning a grapevine in winter with secateurs - Credit: GAP Photos
Pruning a grapevine in winter with secateurs Credit: GAP Photos

If your vine is still young this is what you are trying to create, but if you have this framework already then this is the time to maintain it, cutting back the year’s tangle of growth until all is neatly back where it started. 

Prune wisteria any time between leaf fall and February. Wisteria likes two prunes a year and winter pruning means cutting back summer’s whippy growths to concentrate energy on fruiting buds, and allow resultant flowers to unfurl freely. 

If you pruned in summer you will have already shortened these growths a little, to let in light and air and ripen up the wood for flowering.  Cut these same growths back to two buds, and come May you will have more flowery waterfall than rampant jungle.