Mayday trees (Prunus padus commutata) produce early spring flowers that attract butterflies and bees. The conical white flower clusters give way to dark purple berries, inedible for humans but loved by birds. In fall, mayday leaves turn hues of orange, yellow and red. Pruning mayday trees promotes tree health and controls the shape and size of the tree. Mature mayday trees can reach up to 30 feet in height.
Inspect your tree when it develops leaves, looking for winter injury from storms and heavy snow. If you notice branches that were damaged or broken over the winter, clip them back to the base. Do not cut healthy branches yet since mayday trees only flower on old wood.
Wait until your mayday tree finishes blooming to prune the tree further. This happens in spring.
Check the mayday tree for branches compressing against others. Remove the offending branch at the base; the constant friction damages the wood.
Prune water sprouts from the mayday tree by snipping them off at the base with hand pruners. These grow from the tree trunk or the base of old pruning cuts.
Cut off branches that make less than a 30-degree angle with the trunk, since they are growing too close to it. Also, identify branches growing vertically and cut these off. Remove these at the base with lopping shears, which cut up to 1 1/2 inches of tree tissue. Cut larger branches with a hand saw.
Thin the canopy by removing branches from crowded areas, so air can pass through the mayday tree. Since these trees are susceptible to the fungal disease black knot, thinning helps prevent your tree from contracting the disease. When air passes through the tree, it pushes bacteria through the branches also. Trees with thick canopies are more likely to become infected.
Trim back long branches to a side bud, using hand pruners.