Jennifer Schultz Nelson
Extension Educator, Horticulture
This is a tough time of year for gardeners. At the first hint of warmth, gardeners far and wide are prowling around their landscapes, looking for signs of spring, itching to do something, anything in their garden. Well, it's way too early to start digging around in the garden. The ground is way too wet, and digging now will only create rock-hard soil later. But this is the perfect time of year to prune some kinds of trees and shrubs.
Proper pruning can be intimidating to homeowners, but there are some simple approaches that work in most situations. Assessing and pruning trees on your property regularly is one pro-active measure you can take to reduce the potential for storm damage, and improve the overall look of your landscape.
It is important to begin with sharp pruning shears and/or saws. Bypass-type pruners, which resemble scissors, are preferred to anvil-type pruners which have one sharp blade that comes to rest on a hard opposing surface. Bypass-type pruners tend to cut more cleanly, while anvil-type pruners tend to crush the ends of branches, which can damage them. But they are perfectly fine for cutting up dead branches and general brush cleanup.
Match the right tool to the right job. Most hand pruners can only handle branches up to about 1 ½" in diameter. Larger branches will require different tools such as lopping shears or pruning saws.
Most sources advise gardeners to avoid pruning spring flowering trees and shrubs until immediately after they flower this spring. While you won't harm the tree by pruning now, you will remove many of the flower buds, lessening the number of flowers to enjoy this spring.
Even though they flower in the spring, late winter is a great time to prune fruit trees. However, instructions for pruning specific kinds of fruit trees involves more detail than there is room for in this column. If you have questions on pruning fruit trees, please contact me and I will provide you with plenty of information to guide you.
In general, most pruning is best done during the winter when trees and shrubs are dormant. There are many philosophies on the art of pruning, and many publications dedicated to the subject, but for most basic pruning projects, the primary focus is developing a solid limb structure. Late winter is a great opportunity to have a good look at the limb structure of a given tree or shrub.
Before beginning a pruning project, it may be helpful to spend some time studying the tree or shrub in question, either in person or a picture. While pruning, step back now and then and assess your progress. Remember that once you remove a branch, you can't put it back!
Plan on removing up to one fourth to one third of branches at one time. Removing more than that at one time is likely to cause great stress to the plant and leave you with an unsightly tree or shrub until it recovers.
One exception to this rule of thumb is during rejuvenation pruning. Some shrubs can tolerate every branch being cut back to the ground periodically in late winter or early spring. Not every shrub can handle this, but for those that can, it is a good way to breathe life back into shrubs that appear nearly dead in the center. Good examples of shrubs that thrive with rejuvenation pruning every few years are spirea and red twig dogwood.
Renewal pruning of shrubs is selectively removing about one third of the oldest, thickest branches to invigorate the overall appearance of the plant. It also often improves flowering, by promoting the growth of vigorous new branches.
One general approach to get started on pruning a tree or shrub is to remove crossing branches, as they may rub together and damage each other, remove any vertical twigs, also known as "water sprouts" as these tend to be weak, and remove whole branches whenever possible. If removing a whole branch is not possible, remove the branch up to a sturdy secondary branch.
Removing whole branches requires some attention to detail. Look at where the branch joins a larger branch or the trunk of the tree. There is a ridge of tissue that looks like a turtleneck—this is the branch collar. The collar produces plant hormones that promote natural healing at the cut site. Removing branches with potential to fall on buildings or across power lines is clearly a good idea, but keep in mind that in most cases large limb removal is best left to the professionals.
Use the "3-cut" method to prevent injury to the surrounding bark when removing a tree branch. The first cut is made on the bottom side of the branch, about a foot from the base of the section you want to remove. Cut about halfway through the branch, stopping before cutting all the way through. Next cut from the top, completing the cut you began from below. This removes the bulk of the branch targeted for removal. The last cut falls at the branch collar, and removes the remaining "stub" of the branch.
Leaving a large "stub" of branch extending beyond the collar will not promote healing, and will be unsightly. Cutting the branch off flush with the trunk or larger branch will remove the collar and its healing hormones. The resulting cut will take much longer to heal, and is more susceptible to insects and disease. When pruning at the branch collar, cut at an angle that will allow water to drain from the cut site, and not allow it to pool in the cut, which could promote disease. Use of "pruning sealer" or other such products is unnecessary and not recommended. The tree's natural healing ability is best.
For further information on pruning, feel free to contact the Master Gardener Help Desk at 217-877-6872. We will be happy to assist you with further questions you might have about particular plants in your landscape.