OK to prune shade trees now (April-May)

Asked April 16, 2017, 4:53 PM EDT

We have: 1) a large cottonwood and a flowering cherry with dead limbs; a 15-year Autumn Blaze maple in definite need of pruning/thinning of limbs; and a 15-year aspen and 15-year honeylocust that may need light pruning. Can we do that at this time of year (April-May) or is there an increased risk of disease with the warm weather?

Thanks

Arapahoe County Colorado trees and shrubs

2 Responses

Dead, diseased, and damaged wood can be removed any time of year as needed. Light pruning (up to 10% of the branches) can be done any time of year on healthy trees without stress. However, dormant season (late winter or early spring before buds swell) is considered the best time for many trees. Some trees, such as the cottonwood, aspen and maple, are prone to "bleeding" if pruned in the spring.


Once the leaf buds break open, delay pruning until midsummer after the leaves are full sized and hardened. Midsummer may also be the better time to prune the trees that are prone to bleeding. Timing of pruning is explained in depth at this link:

http://www.ext.colostate.edu/mg/Gardennotes/612.pdf


Other pruning requirements are:

Never remove more than 25% of the branches at any one time, and note that, ideally, branches greater than 2 inches in diameter should not be removed except for one of the reasons stated above (dead, diseased or damaged). Make sure all are clean, branch collar cuts, meaning do not leave stubs. Do not apply wound dressing, as trees are best left alone to heal themselves. Proper pruning is detailed in one of the links below.


Trees will be stressed after pruning, so make sure you provide regular irrigation. Stressed trees do not heal well and can be more susceptible to insects and disease when under stress.


For specific information on pruning, refer to the following links:

http://www.ext.colostate.edu/mg/Gardennotes/612.pdf

http://www.ext.colostate.edu/mg/Gardennotes/613.pdf

http://www.ext.colostate.edu/mg/Gardennotes/614.pdf


Thanks. I've put a reminder in my calendar for next February. Seems like a good idea to do it while the bugs are sleeping.