With its deep purple leaves and showy white spring blossoms, the purple leaf plum makes a nice landscape addition. The tree averages 15 to 25 feet in height and 15 to 20 feet in width. Purple leaf plums grow in hardiness zones 5 to 8. Proper pruning promotes tree health and controls the shape of the tree. Wait until your purple leaf plum tree finishes flowering for the year to prune, in mid to late spring. Pruning before then reduces the display of flowers.
Check your purple leaf plum tree for signs of dead or unhealthy wood. Dead wood feels hollow. Unhealthy wood is either diseased or damaged and may bear scars, wounds, discoloration or growth. It should look notably different from healthy wood.
Prepare a disinfectant by mixing bleach and water in a 1-to-10 ratio in a bucket. Place all pruning tools in the bucket. Clip off all dead or unhealthy wood using your pruning tools. Use lopping shears for cuts thicker than 1 inch and the hand saw for those too large to make with the loppers. Use anvil pruners for small cuts. Cut wood off at the base or prune back to a healthy lateral branch.
Remove branches that rub up against other branches, since this friction will cause damage. Also trim off downward or low-growing branches that impede movement under the tree.
Thin out crowded areas of the canopy to increase air circulation, which helps keep the tree healthy. Remove weak limbs from crowded areas by cutting them off at the base.
Prune back long limbs to a lateral branch to reduce the size of the purple leaf plum tree. Work one branch at a time and use anvil pruners; do not use hedge clippers.
Clip off suckers that grow from old pruning cuts or from the trunk of the tree. These sap energy from your plum tree, grow rapidly, and can weaken the tree if left to stand.