When to prune grapevines
Grapevines are pruned hard every year, but the timing in the sources is not the same. This page shows what two university sources say — Iowa State and the UK Royal Horticultural Society (RHS) — about when to prune, whether bleeding does harm and how many buds to leave. The differences between them are noted. The bud numbers are for one specific training system and may not fit yours.
At a glance
- Iowa State
- Most desirable time is late winter or early spring; in Iowa from late February to early April.
- RHS (UK)
- Main pruning in early winter (late Nov/Dec), when the vine is fully dormant; finish by mid-winter.
- Frost-prone sites
- RHS: delay until March or early April so buds burst later.
- Bleeding
- Iowa State: the sap loss does not injure the vine. RHS: it usually has no significant effect on a healthy vine, but late pruning can weaken it. Nothing can stop it; it ends once the vine starts growing.
- Buds before pruning
- A vine may have 200 to 300 fruiting buds.
- Buds after pruning
- No more than 60 in total (four canes, two wires); 13 per cane on a vigorous vine, 8 on a weak one.
- Fruit
- Grapevines fruit on the previous season’s growth.
- From when
- Pruning and training start in the first winter after planting.
When to prune, according to the sources
Iowa State: the most desirable time is late winter or early spring; in Iowa pruning can begin in late February and should be finished by early April.
RHS: main pruning is in early winter (late November/December), when the vine is fully dormant; it advises finishing by mid-winter, since later pruning leads to bleeding. Larger cuts into older wood also belong in the period up to mid-winter.
The sources do not give one date for all conditions. They describe different climates, so also check local advice for your area.
On frost-prone sites
RHS: if the vine is in a frost-prone spot, delay pruning until March or early April so buds burst later and new shoots are less exposed to frost. Bleeding then usually does not significantly affect a healthy vine.
Does bleeding do harm
Iowa State: vines pruned at this time may bleed heavily, but the sap loss does not harm them.
RHS: bleeding cannot be halted; it stops naturally once the vine starts growing. On trees and shrubs, sap bleeding can sometimes signal disease, insect damage or stress, so unusual bleeding is worth investigating.
How much to remove and how many buds to leave
Grapevines fruit on the previous season’s growth. Before pruning, a vine may have 200 to 300 fruiting buds — without hard pruning the cluster count would be excessive and the vine could not ripen the crop or make enough growth for next year.
- Iowa State’s example is a vine trained on two wires, with four canes.
- On the upper wire keep two of the four canes, one in each direction, and cut them back to 1 or 2 buds — these are renewal spurs that produce next year’s canes.
- Cut the remaining two canes back to 8–13 buds: 13 on a vigorous vine, 8 on a vine with poor vigor.
- Prune the lower wire the same way.
- In total, no more than 60 buds should remain after pruning.
Other training systems
RHS also describes other forms. On rod-and-spur vines the new fruiting shoots from the permanent stem are pinched back in summer and pruned in winter. On Guyot vines the arms that fruited are removed each year and replaced with shoots from last season. It gives no detailed lengths or bud counts.
Common questions
When is the best time to prune grapevines?
The sources differ. Iowa State: late winter or early spring. RHS: early winter, when the vine is fully dormant, and by mid-winter at the latest; on frost-prone sites, March or early April.
Does it harm the vine if it bleeds after pruning?
According to Iowa State the sap loss does not injure the vine. RHS says it usually has no significant effect on a healthy vine, but warns that late pruning causes bleeding that can weaken it. It cannot be stopped and ends when the vine starts growing.
How many buds should I leave?
In Iowa State’s example (two wires, four canes): 13 buds per cane on a vigorous vine and 8 on a weak one, no more than 60 in total. Those numbers are for one specific system and may not fit yours.
Why are grapevines pruned so hard?
Because they fruit on the previous season’s growth and before pruning may have 200 to 300 fruiting buds. Without hard pruning the cluster count would be excessive and the vine could not ripen it.
Important: This page is general background for a home garden and does not replace an on-site look or a specialist's advice. It names no spray products: for crop protection, always follow the product label and the rules in force.
Related calendars
More seasonal tips
Sources
This page was checked against the public reference below. It is general background, not a diagnosis of a specific plant.
- Iowa State University Extension — When is the best time to prune grapevines? (2024)
- Iowa State University Extension — What is the proper way to prune grapevines? (2024)
- RHS — Grapes: pruning and training
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