Quick facts Pruning changes the form and growth of a plant.

Mar 14, If you live in an area where oak wilt occurs, it is critical to prune oak trees before the high risk infection period begins in April. The risk status for oak wilt is updated as weather conditions change, but in a normal year high risk of oak wilt infection occurs in April, May, and June. Check in with My MN Woods to find the current oak wilt risk status before you prune. To avoid oak wilt disease DO NOT prune oaks from April to October.

If oaks are wounded or must be pruned during these months, apply wound dressing or latex paint to mask the odor of freshly cut wood so the beetles that spread oak wilt will not be attracted to the 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.

The primary control line is generally placed between the first and second ring or tier of healthy oaks out from the diseased trees.

Winter pruning is also great for arborists as the harder ground provides them easier access to trees and the bare canopy makes branches easier to see and handle. 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.

Recommended Timing To keep trees' health intact, the safest time to trim is during the late dormant season in winter, typically between the months of February and early April. Because deciduous trees are bare at this time of year, gardeners can easily see the branches to make cuts. Oak wilt covers a large area in Minnesota and affects all species of oak trees. Check the DNR website for an up-to-date oak wilt disease map.

To manage oak wilt Don't prune oaks from April through July to prevent spread by insects.

Sap flow is at an annual high and will quickly spread any infection that may enter through a fresh pruning wound.

Oak trees are best trimmed in the winter between November and March. Oak trees are dormant in winter and are less likely to be negatively affected by pruning when in winter dormancy. That being said, branches which are dead, damaged, or diseased should be Estimated Reading Time: 8 mins.