How and when do I prune a grape vine?

Grape pruning looks intimidating and is one of the most systematic jobs in the garden once the structure is clear. A vine is built as a permanent rod carrying permanent spurs. Every summer each spur produces a shoot that flowers and fruits; every winter that shoot is cut off back to two buds, leaving the spur a little thicker. Repeat for thirty years. The only thing that will hurt you is the timing.

Safety

What you'll need

• Sharp secateurs
• Loppers or a small saw for old wood (optional)
• Soft ties

Step by step

1. Prune between leaf fall and midwinter — this deadline is the whole safety rule.November to December is ideal. From January onwards the sap rises and cuts bleed heavily, which weakens and can kill a vine. If you have missed the window, leave the vine alone until after it has come into leaf and do only light summer work.
2. Identify the permanent structure.The rod is the thick main stem. The spurs are the short knobbly stubs along it, spaced 25–30cm apart and alternating sides. Everything else on the vine is last summer's growth and is temporary.
3. Cut every last-summer shoot back to two buds.Find where the whippy shoot leaves the spur, count two buds out from the spur, and cut just beyond the second. Each year the spur grows a little longer and thicker; that is normal and correct.
4. Shorten the main rod.Cut off about the top third of the rod's previous year's extension, back to firm well-ripened wood, until the rod has reached the height you want.
5. Once the rod has filled its space, stop extending it.Cut the leader back to a bud near the top of its allotted run each winter, and maintain the same spurs indefinitely.
6. Renew a spur that has become too long.Every few years a spur becomes an unwieldy knuckle. Cut it back hard to a bud close to the rod and let a new shoot rebuild it.
7. In summer, thin to one shoot per spur.Each bud produces a shoot; rub out the weaker one so each spur carries a single strong fruiting shoot.
8. Stop each fruiting shoot two leaves beyond the last bunch.In early summer, once the bunches are visible. Pinch out sideshoots from that shoot at one leaf.
9. Thin the bunches to one or two per shoot.This is what decides whether the grapes ripen. A vine carrying everything it sets ripens nothing properly.
10. Tie the fruiting shoots to the wires as they grow.They are brittle at the base and snap in wind. Tie loosely and check the ties.
11. Take off leaves shading the bunches from August.Only the leaves directly shading the fruit, and only late in the season. The rest of the canopy is doing the ripening.

Tips

• The Guyot system, used for wine vines in rows, is different again: it renews the fruiting cane completely each year rather than building spurs. Rod and spur is easier on a wall.
• A vine in a greenhouse is pruned earlier still, in November, because it wakes up sooner.
• If a vine does bleed, it will usually recover, but do not cut it again that year and do not attempt to seal the wound — sealing does not stop it.
• A very neglected vine can be cut back hard to the rod in early winter and rebuilt over two or three seasons.
• Prunings from a healthy vine make excellent hardwood cuttings — pencil-thick sections with three buds, two-thirds in the ground.

Common mistakes

• Pruning in January, February or March — The sap has risen and every cut bleeds heavily. A vine can lose an enormous amount of sap this way and be seriously set back or killed. Prune before midwinter.
• Leaving last summer's shoots full length — The vine extends further every year, fruits further from the rod, and becomes an unmanageable tangle that ripens nothing.
• Cutting the spurs off flush with the rod — The spur is the permanent fruiting point. Cutting to two buds is what keeps it; removing it entirely means starting that position again.
• Skipping the summer work and relying on winter pruning alone — Stopping shoots and thinning bunches in summer is what makes the grapes ripen. Winter pruning only sets up the structure.

Keeping on top of it

• Winter prune all shoots back to two buds and shorten the rod (Annually, November to December)
• Thin to one shoot per spur and tie in (Annually, late spring)
• Stop shoots two leaves beyond the last bunch (Annually, early summer)
• Thin bunches to one or two per shoot (Annually, early summer)
• Remove leaves shading the bunches (Annually, from August)

Questions people ask