Plum trees need regular pruning to prevent fruiting branches from aging prematurely and to ensure good yields. Here’s how to do it properly.
When Should You Prune a Plum Tree?
The best time for structural pruning is mid-summer, from late July to early August. Pruning in late autumn or winter is also possible, as it provides a clearer view of the tree’s structure without foliage.
Types of Pruning for Plum Trees
- Planting Prune
- Training Prune
- Maintenance Prune
Plum trees and varieties like Damsons, Greengages, and Mirabelles naturally grow upright and develop narrow crowns. To allow fruits in the inner branches to receive ample sunlight and develop full flavor, training pruning during the first few years is crucial. Shorten main branches (« redirect ») to an outward-growing side shoot for better light penetration.
Planting Prune
Plant plum trees between late autumn and early spring, but perform the planting prune the following spring.
- Leave the central leader and about four evenly spaced lateral branches around the trunk.
- Train these lateral branches as scaffold limbs by shortening them by one-third to an outward-facing bud.
- Remove steep, upright competing shoots to prevent issues or branch breakage later.
Training Prune
To shape a young plum tree:
- Regularly remove water sprouts (non-woody shoots) in late spring or summer.
- Select about 8 strong, outward-growing lateral branches per scaffold limb in early spring, and shorten them by half to an outward-facing bud.
- Remove unnecessary interior branches, shortening them to about 10 cm.
Maintenance Prune
For mature trees, perform light thinning after the harvest, around mid-August:
- Remove aging fruiting branches over three years old.
- Shorten older side branches to an outward-growing younger shoot.
- Eliminate upright and inward-growing shoots (water sprouts).
To maintain the tree’s shape and ensure fruit production:
- Thin out scaffold and fruiting branches inside the crown.
- Redirect aging or hanging fruiting wood to younger, two-year-old shoots with flower buds.
Rejuvenation Pruning
Avoid heavy pruning of plum trees unless necessary. For neglected trees:
- Remove all steep, upright shoots.
- Ensure cuts are not wider than half the diameter of the branch being removed to prevent large wounds and fungal infection.
- Leave 10 cm stubs on thicker branches to encourage regrowth, and remove these after 1–2 years.
- Redirect aging fruiting wood to younger, interior branches.
Practical Tips
- Older, vigorous varieties like ‘Brompton’ or ‘Myrobalan’ are being replaced by smaller, less labor-intensive varieties like ‘St. Julien A’ or ‘Pixy’. These smaller forms are ideal for home gardens.