Mar 14, If you have oaks in your landscape that need pruning and you live in an area of Minnesota where oak wilt occurs, pruning must be done before the oak wilt fungus and it's insect vector become active.
Oak wilt is a fatal disease of oak trees that can be found in some counties of Minnesota. If you live in an area where oak wilt occurs, it is critical to prune oak trees. Oak trees should be pruned in the winter months when the trees are dormant and beetles are inactive to prevent the spread of oak wilt.
Winter pruning is also great for arborists as the harder ground provides them easier access to trees and the. The best time of year to prune oak trees is from late fall until the end of March, when oak wilt disease is dormant and there is no risk of infection.
If your oak tree is pruned at any other time of the year, some type of sealant should be applied to all pruning wounds to prevent oak wilt infection. Pruning paint is effective along with any latex paint. Sep 21, The University of Minnesota Forestry Department posts the oak wilt risk levels for pruning oaks: high risk in April through June, low risk in July through October, and no risk in November through March.
You can safely prune Minnesota oaks in winter and take appropriate precautions as needed to protect the health of your tree.