Winter is the best time to prune trees, while they’re still dormant.
Yes, it’s cold for you, the tree trimmer. But pruning in the winter is kinder to plants. It discourages sap flow from the cuts, inhibits the spread of disease (like oak wilt) and gives deciduous and blooming trees time to recover before the spring growth period. And happy trees are helpful trees. They shade our houses, provide wind breaks and counter climate change.
Here are a few tips from the Texas Trees Foundation and AgriLife Extension Service at Texas A&M University.
- Never remove more than 25 percent of the entire leaf area of a tree and never “top” or “bob” your tree. This can weaken the tree and make it more susceptible to limb breakage in high wind or ice events.
- Crown reduction pruning can be used to reduce the height of a tree (sometimes necessary because of power lines or visual sight lines), but it should be used infrequently. With taller trees, too, this type of pruning may be best left to professionals.
- Take care to not damage bark on the trunk of the tree or shrub when pruning branches. (See diagram.)
- Always use clean and sanitized tools to avoid spreading fungi, bacteria and viruses across plants. You can sanitize with 70 percent denatured alcohol, soaking tools for 1-2 minutes according to the AgriLife Extension service at Texas A&M University.
- Use the “three cut method” for removing limbs of greater than two inches. This is a method that allows the large branch to be supported until the final cut. (And it’s a bit complicated. See details at the website Tree Care Kit and don’t let just anyone operate the chain saw! The USDA Forest Service Tree Owners manual also has detailed instructions, and is even more cautious about chain saws. If power tools are required, call a professional, the manual urges.)
Final tip, for those of you in the Southern half of the U.S., please don’t commit crape murder.
You won’t be arrested, but you may be sorry. Shearing off the tops of crape myrtles to create a vase-like display of flowers when the trees next bloom, seems smart, because it does force a pop of large color. But it is not helping the plants and can restrict their life.
Texas A&M horticulturalist Greg Grant has written an an impassioned, humorous appeal to stop the practice. "We don't hack on dogwoods, redbuds, or Japanese maples," Grant argues. "So why do we pick out the prettiest one of all [crape myrtles] to maim? … How sick can we be to pick out the prettiest belle at the ball and scratch her face?"