Plant Palette

Plant Palette

Pruning

Photo of Jennifer Schultz Nelson

Jennifer Schultz Nelson
Extension Educator, Horticulture
jaschult@illinois.edu

Working out in the yard may not be the first thing that comes to mind this time of year, but it is the perfect time for pruning many woody plants in the landscape. But before you run out and start pruning everything in your yard, there are some general guidelines to consider. It is also worth doing some research on the specific plants you plan to prune, especially if the plant in question has never been pruned. Remember, once you prune a branch away, you can't reattach it!

Proper pruning can be intimidating to homeowners, but there are some simple approaches that work in most situations. Assessing and pruning trees and shrubs on your property regularly is one pro-active measure you can take to improve your landscape. Make sure your pruning tools are in good repair and most importantly, make sure they are sharp! Pruning with dull pruning shears may tear limbs more than cutting them, causing more harm than good.

Pruning is best done during the late winter when trees and shrubs are dormant. A big exception to this advice is spring flowering shrubs. Pruning spring flowering shrubs such as lilac and forsythia in the dormant season will remove that spring's flower buds. The best time to prune spring flowering trees and shrubs is right after they flower.

There are many philosophies on the art of pruning, and many publications dedicated to the subject. We have several publications available at our office about general tree and shrub pruning, as well as more specialized topics such as fruit tree pruning. Please call or stop by if you are interested in this information.

One general approach 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.

Use the "3-cut" method to prevent injury to the surrounding bark when removing a large branch that cannot be cut cleanly with pruning or lopping shears. The first cut is made with a saw 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 plant's natural healing ability is best.

If in doubt about pruning trees, call a certified arborist. It may be tempting to save money by attempting to remove damaged or unwanted limbs yourself, or to hire the first person to show up on your doorstep with a saw, but a wrong move that sends someone to the hospital, or sends the remainder of a tree toppling onto your home or car will quickly eat up any money saved. Certified arborists are listed in the phone book, or you are always welcome to call our office at 877-6042 for help in locating one.

There are several reasons to prune woody plants, but one often overlooked reason is to maintain and promote plant health. Pruning removes dead or damaged limbs that if left alone could promote development of disease of infestation by insects. Pruning also maintains the plant's purpose in the landscape, whether that is pruning an apple tree to maximize fruit production, or pruning a hedge to maintain it as a dense border to your property.

A common reason given for pruning is to improve a plant's appearance and form. This includes removing vigorous growth called suckering at the base of many trees and shrubs. Whether the pruning is actually an improvement on a plant's appearance may be up for debate. It always seemed to be my job growing up to help my dad prune the yews that line the front of the house, each one carefully shaped into what to me look like big green meatballs. But my dad loves them and that's just fine. At my house, we have no yews.

In pruning to improve appearance, you can also control a plant's size. But choosing the right plant for the right place can reduce the need for constant pruning to keep a plant within a particular area. If you were to plant a shrub that has a mature height of ten feet in an area that really can only accommodate five feet, chances are you will be fighting this plant's natural form constantly, pruning it just to keep it under control.

Now if you were to instead plant a shrub in that same space that had a mature height of five or six feet, you could prune the shrub to control the form as it matures, and at full-size chances are the shrub would need very little pruning, since its natural form would fit the space. This approach creates a lot less work in the long run.

Pruning is often necessary to protect people and property-- a fact many of us discovered after the ice storm in 2006 when many tree limbs dangled precariously over homes all over the city. That situation was an obvious danger to residents. But there are other situations not as obvious. A branch overhanging a home's roof provides a means for wildlife both large and small to have access.

Several years ago a tree adjacent to my parent's house had grown large enough to overhang the house. It went unnoticed until one day while making dinner my mom nearly jumped out of her skin when she heard loud chattering that sounded like a squirrel was falling down out of the kitchen ceiling! Squirrels had gotten onto the roof from the overhanging branch and were trying to get into the exhaust fan vent from the kitchen which happens to be on the roof.

Overgrown branches may threaten safety and security of your family. If branches from trees or shrubs are obscuring your view when exiting your driveway, pruning may be in order to prevent a traffic accident. If trees or shrubs obscure the entry to your home, this could provide a burglar or other criminal a place to hide.

Whether for safety or aesthetics, a bright winter day is a great time to prune. Without leaves on trees and shrubs, you can clearly see the branch structure. As an added benefit, it is a good remedy for the cabin fever that starts to strike this time of year!

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