The late dormant season is best for most tree pruning. Pruning in late winter, just before spring growth starts, leaves fresh wounds exposed for only a short length of time before new growth begins the wound sealing process. Another advantage of dormant pruning is that it’s easier to make pruning decisions without leaves obscuring plant branch structure. Pruning at the proper time can avoid certain disease and physiological problems.

By utilizing the following recommendations, the spread of certain tree disease and physiological problems can be avoided. Do not prune oak trees during the months of April through October. Doing so during these months can cause oak wilt and spread the disease. Prune honey locusts when the trees are dormant in late winter to avoid the increased likelihood of stem cankers. Apple trees, flowering crabapples, mountain ash, hawthorns and shrub cotoneasters should be pruned in late winter to avoid infections, fireblight bacterial disease and dying or die-back. To prevent tree sap bleeding from free flowing sap trees you should prune maples, box elders, butternut, walnut, birch, ironwood and blue birch after their leaves are fully expanded in late spring or early summer. When pruning any tree never remove more than one-quarter of the trees live foliage.

To promote plant and tree health its recommended to remove dead or dying branches, remove branches that rub together, remove branch stubs and avoid topping of trees. Avoid the removal of large branches, as this may leave behind stubs that can cause several health problems and also destroys the plant’s natural shape and promotes suckering and development of weak branch structures.

Proper tree pruning encourages flower and fruit development, maintains a dense hedge and a desired plant form or special garden form. Pruning can be done to improve plant appearance by controlling the size and shape of the tree, keeps evergreens well-proportioned and dense and removed unwanted branches, waterspouts, suckers and undesirable fruiting structures.

Pruning and proper tree maintenance can protect people and property. It is recommended that split, cracked or dead branches and limbs are removed before they cause a safety hazard. Hazardous trees should be taken down and branches that obscure vision at intersections or those that hang low over sidewalks should be pruned.

Editor’s Note: The City of New Ulm presents a weekly column highlighting activities in different departments in the city government. Once a month the city will answer questions from readers. Questions on New Ulm city issues can be sent to comments@ci.new-ulm.mn.us.