Pruning a plum tree (Prunus domestica subsp. domestica) is a key step in ensuring healthy growth, abundant fruit, and a long lifespan. While commonly confused with plums, the damson plum – often called Zwetschge, Prüm, or Quetsche depending on the region – is actually a distinct subspecies. With its smaller, oval-shaped fruit, the damson plum tree requires a slightly different pruning approach to encourage optimal growth.
When to Prune Plum Trees
Plum trees can be pruned in either winter or summer, with each season serving a specific purpose:
- Winter Pruning (November – March):
- Best done on frost-free days.
- Allows easy assessment of the tree’s structure when it’s leafless.
- Promotes vigorous growth and branching in the following season.
- Summer Pruning (Late June – August):
- Slows down growth, reduces the formation of new shoots, and controls tree size.
Additionally, the tree’s age and growth stage determine the type of pruning it needs. The three main types of cuts are:
- Training Prune (for young trees)
- Maintenance Prune (for mature trees)
- Rejuvenation Prune (for older trees)
Important Tips
Avoid pruning during frost, heavy rain, or extreme heat, as these conditions increase the risk of disease or stress to the tree. Regular annual pruning is preferred over drastic cuts, as plum trees don’t heal large wounds well.
How to Prune Damson Plum Trees
Regular pruning ensures the tree grows into a beautiful, full-crowned shape while boosting fruit production. Here’s how to prune your plum tree:
1. Planting Prune
Performed during the tree’s first planting:
- For spring planting, prune immediately. For autumn planting, wait until the following spring.
- Select 3–4 evenly spaced branches to serve as the scaffold limbs. These will form the tree’s structure.
- Remove vertical shoots near the trunk, and shorten the selected branches by one-third of their length.
2. Training Prune for Young Trees
In the first 5–9 years, prune annually in late winter (February – March) to develop a pyramidal crown.
- Focus on outward-facing branches: Choose side branches growing away from the trunk and space them evenly.
- Remove competition: Eliminate branches that compete with the central leader or scaffold limbs.
- Thin the crown: Remove inward-growing or overly dense branches to allow light and air circulation.
3. Maintenance Prune for Mature Trees
Mature trees require regular maintenance to maintain their shape and increase fruit yield:
- Remove dead, diseased, or weak branches.
- Thin out overly dense areas in the crown to improve light penetration.
- Shorten overly long branches to maintain balance.
4. Rejuvenation Prune for Old Trees
For neglected or aging trees, prune gradually over several years to restore vitality.
- Focus on removing dead wood and thinning overcrowded areas.
- Avoid cutting branches larger than 5 cm in diameter to minimize stress.
- Limit reductions to a quarter of the crown per year.
Caring for Plum Trees After Pruning
Pruning can leave the tree vulnerable to pests and diseases. Here’s how to protect it:
- Regularly inspect the tree for signs of disease.
- For cuts larger than 3 cm in diameter, apply tree wound sealant for additional protection.