Grapes fruit on new shoots that grow from last season's canes
Grapes fruit on new shoots that grow from last season's canes, and only a few well-placed canes are kept. Prune hard every dormant season, in late winter after the coldest weather but before the buds swell. Removing about 80 to 90 percent of the previous year's growth is normal and necessary. Under-pruning is the common mistake and leaves a tangled vine with fewer flower buds and small, poor-quality fruit.
Promising A person has checked it against its sources. If you skip this, it still grows, just less well. The planner suggests it.
How it works
Fruit forms only on shoots arising from last season's canes, so a vine left unpruned piles up old wood that no longer fruits while the crop crowds onto too many buds. Cutting back 80 to 90 percent of last year's growth concentrates the vine into a small number of well-placed, productive canes; prune too little and too many buds remain, so the vine over-produces small, poor fruit and becomes a tangled mass.
What to do about it
Prune while the vine is fully dormant, after the coldest part of winter, before the buds begin to swell, around February to March. Remove roughly 80 to 90 percent of the previous year's wood, keeping a few strong, well-placed canes (and renewal spurs) according to your training system. Do not under-prune.
How much it matters: The one figure, about 80 to 90 percent of last year's wood removed at dormant pruning, is stated by both sources (Illinois "80 to 90%", Maryland "90 percent"). The direction of the consequence (fewer flower buds, small poor-quality fruit, and a biennial bearing pattern) is sourced; no other magnitude is claimed. Because pruning is the gardener's annual dormant-season choice, the rule only advises.
The evidence
Evidence: checked against 2 sources in the research-based literature.
The 2 sources
Proper pruning often results in the removal of 80 to 90% of the wood
Typically, 90 percent of the previous year's growth is removed during dormant pruning
Plants it applies to
How this rule has changed
Every change is dated, newest first. The full record, with each reason, is in the data download.
- Wording made clearer
- Added to the rules
Cite this page
Milpa Gardens. "Grapes fruit on new shoots that grow from last season's canes, and only a few well-placed canes are kept. Prune hard every dormant season, in late winter after the coldest weather but before the buds swell. Removing about 80 to 90 percent of the previous year's growth is normal and necessary. Under-pruning is the common mistake and leaves a tangled vine with fewer flower buds and small, poor-quality fruit." Evidence grade: Promising. https://milpa.garden/rules/grapes-fruit-new-shoots-that-grow-from/
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