Apple tree pruning

Asked March 13, 2018, 3:18 PM EDT

I live in Two Harbors and have an apple orchard of about 85 trees. About half are Haralson and the rest are a variety. The orchard is chemically free and we have had few problems with disease or insects. The majority of the tress are mature. Last year most of the trees had apple scab. That year we were not able to prune the trees as well as usual and now they seriously need pruning. Because of the weather we are not going to be able to prune all of the tress before they bud out. My question is - Can we prune the mature trees in the summer without damaging the tree? We are not concerned with apple production. We appreciate your help.

Lake County Minnesota

1 Response

The best time of year to prune apple trees is in February or March, when the tree and the fire blight bacteria are dormant. Summer pruning in late July or August is another time when pruning can be performed, but severe pruning at this time will weaken the tree. Therefore, the majority of pruning should be done during winter or spring.

If summer pruning is required it should be done after laterals have six inches of growth in mid-July to avoid a second pinching. The prime fire blight conditions are past. Fire blight may spread to trees if the weather is not dry and hot. If you get fire blight then infected branches should be pruned back eight inches closer to the trunk than the apparent infection. Between cuts, disinfect pruning tools with a 10% bleach solution or an anti-bacterial cleaner such as Lysol or Listerine, to avoid spreading the disease. Burn cuttings or include them in your trash.