University of Illinois Extension

Pruning

Pruning may seem like a natural thing to do in late winter and early spring, but a University of Illinois Extension horticulture educator cautions that it depends on what you want to prune.

“Some woody plants can be successfully pruned in late winter/early spring, but others should be pruned at another time,” said Sharon Yiesla, who is based in Lake County. “Deciduous trees--those that lose their leaves in the winter--can be pruned while they are dormant. This is actually a good time, since it is easy to see the framework of the tree. Seeing the framework makes it easier to decide what needs to be removed.”

Pruning trees that have been in the landscape for a while consists mostly of maintenance pruning. She recommends removing branches that have been damaged by fall and winter storms, any branches that are crossing one another and branches that appear to have been attacked by disease and insects during the growing season.

“After that has been done, remove branches that will help improve the shape and form of the tree,” she said. “Do not cut just to be cutting. Always prune with a purpose.”

Pruning shrubs in late winter/early spring takes a little thought, she noted.
“Shrubs that will bloom in the spring should NOT be pruned now,” she said. “They formed their flower buds last summer and, if they are pruned now, spring flowering will be greatly reduced.

“Spring-flowering shrubs should not be pruned until after they are finished flowering. Shrubs that bloom mid-spring-to-summer can be pruned in March since they will not form their buds until spring time.”

Too often, shrub pruning consists of lopping off the top few inches of the shrub. Take time and do it right..

Sharon Yiesla

When pruning shrubs, it is best not to just “give them a hair cut,” Yiesla said.
“Too often, shrub pruning consists of lopping off the top few inches of the shrub. Take time and do it right. Prune selectively.”

There are two main types of cuts to make, she added. Thinning cuts are made to remove a branch at the point where it emerges from the ground. Cutting out older branches to the ground will not only stimulate new growth but will start to lower the height of the shrub.

“Doing this type of pruning on a yearly basis helps keep shrubs from becoming too tall while maintaining a natural shape,” she said. “This type of pruning is perfect for shrubs with several medium to large stems emerging from the ground, like old-fashioned lilac and red twig dogwood.”

The other type of cutting is known as ‘heading back.’

“With this cut, only a portion of a branch is removed back to a side branch or bud,” Yiesla said. “Making a number of heading back cuts at different heights helps to open the shrub to sunlight and air circulation, which can reduce disease problems and enhance future flowering.

“As you look to prune shrubs, remember that good pruning is often a combination of both thinning cuts and heading back cuts.”

Yiesla said that pruning cuts do not need to be painted or sealed.

“Just be sure to make good, clean cuts with sharp tools,” she said. “Do not leave stubs as these will not produce new growth and may be entryways for disease and insects during the growing season.

Your cut should be made near the bud, since this is the area from which new growth will emerge.”