How to Trim Pin Oak Trees

Pin oaks (​Quercus palustris​, USDA hardiness zones 4-8) are beautiful, fast-growing shade trees with leaves that turn brilliant shades of bronze and red in the fall. They have unusual lower branches that curve toward the ground, which can give them a striking look, but sometimes, these branches need to be trimmed, so knowing how to trim a pin oak tree is a valuable skill.

To preserve the health of the tree, pin oaks must be trimmed properly. Some trees can be pruned at any time of year, but oaks, including pin oaks, should only be trimmed when they are dormant. Tree experts suggest trimming oaks after a hard frost, so in much of the United States, November through February is the best time to trim an oak tree. All oak trees, including pin oaks, are susceptible to oak wilt disease, and trimming a tree even in early fall can increase the chances of your tree getting this disease.

If your oak tree is less than three years old, you should only trim broken or dead branches. Once your tree starts to ooze sap in the spring, it's too late to prune. That's when sap beetles can infect your tree with oak wilt, a fast-spreading fungus that can kill even the most majestic of oak trees.

When you trim branches, make sure you sanitize the blades of your pruning shears, loppers or pruning saw first by dipping them in 70 percent or higher isopropyl alcohol, and wipe the blades with alcohol before making each subsequent cut.

Here are some tips to ensure your trimming is successful:

• Once you start trimming, only trim branches that are growing toward the main tree trunk.
• Make sure your tools are sharp and never remove more than 25 percent of the tree.
• When you cut a branch, you are opening that tree to potential disease like oak wilt, so make sure there won't be a sudden warm spell. If you trim your tree properly, you will eliminate branches growing on top of each other and improve the tree's health by exposing it to more air and sunlight.
• Trim the branch about 3 inches from the main trunk of the tree and cut from beneath the branch about 1/3 of the way through the branch. This is to avoid tearing the branch off. Then, cut just past this first cut, working away from the trunk. When that cut is made, go back and finish cutting the remaining part of the branch.

Pin oaks are native to the Eastern United States as far west as Wisconsin and Arkansas, although they can be found throughout most of the U.S. They grow in a symmetrical, pyramid shape, as tall as 60 to 70 feet with a 20- to 40-foot spread.

If a pin oak is properly cared for, it can provide many years of shade and enjoyment. Pin oaks tolerate urban settings, although they do not do well in alkaline soils. Plant a pin oak on rich, acidic, well-draining soil in a sunny location, and it should do well.

If your soil is alkaline, you'll need to amend the soil around your pin oak with acidic or iron-rich soil amendments or a tree fertilizer in order to prevent it from developing iron chlorosis. Pin oaks produce acorns that become food for songbirds, wild turkeys, deer, squirrels and ducks.