Plum trees (Prunus sp.) are spring-blooming and summer-fruiting stone fruit trees. When plum trees become overgrown, the tree's health can be compromised, fruiting production can slow and it becomes difficult to harvest fruit from the tree. Keep tree health, vitality and size in check with an annual session of pruning. Plum trees bear their fruit on both new shoots and old spurs so pruning practices take this into account by preserving and promoting new growth.
Prune your overgrown plum tree when it is in its dormancy, after Feb. 1 but before the flower buds swell and burst open in early to midspring.
Cut off any dead, diseased, cracked, broken or abrading or entwined branches first. Place cuts down into healthy wood just outside the slightly swollen branch collar of the parent branch or trunk.
Remove any water sprouts growing straight upward in the canopy or inward toward the trunk along with any shoots emerging from the root zone and lower trunk. Also remove any branches that come into contact with the soil or within 12 inches of the soil to help prevent the transfer of disease.
Head back any outsize tips of branches that exceed the length of the upright central leader branch at the centre of the canopy. Bring the branch tip down to be in line with the desired size of the canopy, placing the cut 1/4 inch above a leaf node or bud.
Use the proper cutting tool for the right size of branch to avoid damaging the surrounding tree tissues. Secateurs work for tender growth less than 1/3 inch in diameter. Loppers are best for branches and shoots larger than 1/2 inch and a fine-toothed pruning saw is recommended for anything larger.