Hold off on pruning during warm spell?

Asked February 6, 2019, 8:01 AM EST

I'm a professional tree and shrub pruner. We've had a nice, cold winter thus far and I've begun work. This week, however, we've had temps got the 50s for 2-3 days. My question is, should I hold off on significant pruning until weather gets cold again? My fear is whether the trees will initiate sap flow in this warm spell and then if we get a sudden deep freeze , will that cause sap/water expansion and potentially harm the trees? Thanks,. Matt

Cheboygan County Michigan pruning trees pruning shrubs

1 Response

Light pruning and the removal of dead wood can be done anytime.

Pruning in the late summer or early fall can stimulate new growth that may not harden off before the cold weather. This is not a concern during the winter. Pruning live limbs during a winter warm spell should not be a concern.

Pruning during dormancy is the most common practice. It results in a vigorous burst of new growth in the spring and should be used if that is the desired effect. It is usually best to wait until the coldest part of winter has passed. Some species, such as maple, walnuts and birches, may “bleed”—when the sap begins to flow. This is not harmful and will cease when the tree leafs out. Generally, you can prune up to the time when buds begin to plump up. From mid-November to mid-March, you can shape and thin trees in preparation for the spring season ahead.

The job should be handled before new spring growth begins, but after the threat of severe cold has passed.

Evergreens, on the other hand, in most situations should be pruned in the growing season, since they never become fully dormant and may suffer tip burn if pruned in the winter.