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When to trim oak trees
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After buying a house with a big oak tree in the front yard, I’ve been wondering when the best time is to trim an oak tree. Fortunately, I found some really helpful tips from several State Extension offices.
Oak tree trimming is best done in the winter between November and March. Oak trees are dormant in winter and are less likely to be negatively affected by pruning when in winter dormancy. That being said, broken branches that are dead, damaged, or diseased should be removed any time of year (and as soon as possible).
There are lots of factors that affect the timing of oak tree trimming. Read on to learn more about when to trim an oak tree (and when NOT to prune trees).
Timing considerations for when to trim oak trees in your yard
The best time to prune live oaks is during winter dormancy. In most areas where oaks grow, trees tend to be entering dormancy by late November and are usually still in dormancy in early March. Whenever you do decide to prune, remember not to remove any branch without a reason!
The sap in the tree is not flowing during dormancy. Growth is pretty much on hold. There are fewer active processes that could be harmed by a wound or load shift caused by pruning. Try to trim oaks in the winter when fluids are not actively moving through the trunk and branches. Get them while they’re sleeping….
While these beautiful trees don’t always lose all their leaves in the fall, they will have substantially fewer leaves in the winter than in the summer. Fewer leaves mean that the branches are easier to see and follow with the eye as you plan your pruning.
When the tree “wakes up” in the early spring, it will have the energy to put towards healing the pruning wound. This timing will help the oak tree recover quickly and will minimize risk.
When not to trim oak trees: Pruning considerations for seasonal growth & overall health
The worst time to trim oak trees is during peak spring growth. From mid-March until the end of June, oak trees are very busy growing! This is not the time to stress them with pruning. Sap flow is at an annual high and will quickly spread any infection that may enter through a fresh pruning wound.
So, April-June is the worst time to trim oak trees, as the trees are in full growth mode. Pruning wounds are an easy access point for harmful bacteria and other nasty pathogens. Oak wilt is of particular concern. The tree has also just used stored energy to grow shoots and leaves. It needs time to recover! August-October is considered less risky for pruning, but most homeowners wait until dormancy to trim oak trees.
Read more about Oak Wilt in this article from the Michigan State University Extension.
Try not to prune oak trees during the early spring-summer season. Your tree will likely be healthier if you wait for winter pruning unless it’s an uncommon situation.
Resist spring and summer pruning unless it is truly necessary. Try to remember that pruning wounds heal best if the cuts take place before the spring growth flush. Minimize warm weather oak pruning!
Tips for pruning oak trees in the winter
Oak trees are best pruned during winter dormancy. There are, however, a few considerations for pruning oak trees in wintertime.
Some homeowners choose to trim oak trees in late November or early December, just as they enter dormancy. Most of the leaves have fallen and the frame of the tree is visible.
Pruning in early winter allows the homeowner to remove any extra-long branches or other branches that might not be able to hold snow or wind loads. It can also be easier to work in the area around the tree before there is a lot of snow on the ground.
Early spring is also a great time to prune, provided it’s before the oak trees are out of dormancy. It can be difficult to see which branches are dead during this time of year, but it’s easy to see the general form of the tree.
The tree doesn’t have as much leaf cover during winter dormancy, making the frame easier to see. Now that it’s tree trimming season, remember not to go TOO far with the whole oak tree pruning thing. This is not the time (nor is it ever the time) to start randomly cutting off branches. Make a plan before you start pruning!
Pruning is more than just indiscriminately removing branches. Proper pruning includes knowing which branches to remove, when to do it, and how to minimize damage to the tree.Iowa State University Extension & Outreach, Pruning Landscape Trees
Oak trees are generally pruned to have a dominant central leader branch. That means that there is one branch in the middle that is taller than the others (like a Christmas tree). Remember that having multiple leader branches creates a weaker tree.
Try to train a tree to have only one leader to help strengthen it for extreme weather. “Topping” landscape trees are generally discouraged as it can weaken the whole tree. It’s also prudent to research the type of oak tree you have to learn more about its common habit (shape).
This article from the University of Florida has helpful background information on why landscape trees need trimming (as opposed to trees in a natural forest).
Types of oak tree pruning that can be done any time of year
My Grandpa always said that the best time to prune is when you’ve got the pruners in your hand. He was joking around, but there is a grain of truth to this. There are some types of tree pruning that can be done any time of year.
Both new and mature oak trees can be pruned any time of year for the purposes of removing dead, damaged, or diseased branches. Get them out of there as soon as is safely possible! But don’t go trimming off healthy branches just because you’ve got the pruners in your hand.
It’s also prudent to remove any healthy branches that may cause a safety concern. If a branch is impeding a walkway or otherwise creating a risk, removal is often necessary. Trees are trimmed to prevent or address safety risks at any time of year.
A healthy oak tree should be able to withstand a bit of pruning even in the “wrong” season. This can be a good opportunity to make sure the tree is in a healthy environment, including that it has access to adequate water, sunlight, and air movement.
Other considerations for seasonal timing the pruning of oak trees
Oaktree pruning should be done at least once a year to help the tree shape. The central leader trunk should always be the tallest, largest branch. Branches that cross other branches are good candidates for removal, as are inward-growing branches and branches that can no longer get any sun.
Prune off only a little bit each season rather than doing a large renovation pruning every few years. Don’t get too ambitious in a single calendar year. The oak tree needs leaves to make its food! It’s not a good idea to prune off more than 1/3 of the leaves in a one-year period. The tree needs an adequate leaf canopy to grow strong roots, withstand winter cold, and grow next year’s leaf canopy.
It’s also important to schedule your oak tree trimming for when you have time to do it properly. Proper trimming includes disinfecting pruning tools before you start….all the way to taking the tree trimmings to the compost. Make sure you have adequate time available.
Trees can be left to heal their own cuts in the open air. Healthy trees seal proper pruning cuts on their own. Step away from the can of sealant and let the tree do its thing!
Further reading on proper tree trimming is available in this article from Iowa State University Extension.