Pruning a plum tree is important if you want your tree to produce fruit continually and stay healthy. Knowing when, where and what to prune are essential to keeping your plum tree looking great -- and the plums tasting great -- year after year. By following a few simple steps, you can have your plum tree pruned faster than you can say "pruned plums" five times fast.
Prune in June. This is the best time to make cuts. When pruning, make clean cuts to avoid splitting or fraying the wood. Also, if a cut is 5 cm (2 inches) or less, there should be no need to seal the now-bare wood, but if it's larger, you may wish to either seal it with a protective sealant or simply trim the branches with a slant that slopes down towards the tree. This prevents water damage.
Remove anything that looks sick, dead or dying. Also, cut loose any damaged pieces that may be stuck in the tree.
Cut the first branch of your baby plum tree 90 cm (3 feet) above the soil if you want it to grow into a bush. Prune 1.2 metres (4 feet) above the soil if you hanker for a big old plum tree, and snip just 60 cm (2 feet) up if you intend to shape your tree into a pyramid.
Leave a bud after each cut. In the infancy of your plum tree's life, prune just above a bud and then remove the top bud. Be sure there are a few buds further down the branch.
Trim 46 cm (18 inches) from a bud on your plum tree in its second season. Make this cut along that first brave branch. Trim the rest of the branches to about 25 cm (10 inches) long, always snipping just before a bud.
Repeat your pruning in the third year exactly as you did for year two.
Look for your original first branch when it's about 2.5 metres (8 feet) high. Snip this branch so that it towers about 90 cm (3 feet) over the rest of the growing tree. Prune back anything that was new growth and yielded no fruit, thus ensuring fruit next year.
Watch out for signs of silver leaf, an infection that plagues many plum trees.