Phyllis Both color for BNR

Phyllis Both

“He who has not Christmas in his heart will never find it under a tree.” – Roy L. Smith

As I am writing this, I am seeing a swarm of mosquitos out the window. What is going on? This weather makes you want to get ahead of spring by trimming trees or cleaning the rest of the garden. I have written about tree trimming often but a reminder is always helpful.

Why should you prune your trees? For future health of tree, safety, and aesthetics.

The best time to prune is in the late, dormant season (February). This is important because you avoid disease problems and physiological problems. The ground needs to be frozen well before pruning. Right now the weather is great for us but not for pruning trees.

In the dormant season, the wound from trimming is only exposed for a short time before new growth starts. It is also easier to shape your tree when there are no leaves. Always prune your trees next to the collar. Do not leave long branches. A 3-point cut works well so you do not strip the bark or leave jagged edges. First, undercut the tree branch partway through the branch. Then cut it off in front of that cut. Finally, make a final cut at the tree collar. This should prevent the tree from tearing. If this sounds confusing please email me and I will get an instruction pamphlet to you.

If you have oak trees, never prune between April 15 and October. Spring and summer pruning increases chances of disease. Maples will bleed if the day temperatures are above 40 degrees so prune in February or better yet January. Never prune more than 25 percent of the tree each year.

Evergreens require little pruning but if you have large branches they can be pruned during the winter. If you start when your evergreens are young, you just need to prune the candles (new growth). After the growth is finished in spring, I like to pinch off two-thirds of the candle. This keeps the pines and spruces nice and compact. Never prune the leaders except if there are two leaders. If there are two leaders, prune off the less desirable one.

Some evergreens can be sheared and shaped all summer until September. This includes arborvitae, yews, hemlock, and juniper. Do not prune severely since the inside of these trees are brown in the center. Leave some green on the outside.

To summarize pruning trees: have a reason, prune when dormant (except when a branch is rubbing or broken), never use pruning paint (except on an oak that needs to be trimmed in the off-season), remove only 25 percent of the tree, make cuts at branch collars, use correct tools and disinfect after use (Lysol spray is fast and easy).

People ask about fertilizing trees. The rule of thumb is that if you fertilize your lawn then you are fertilizing your trees since the roots that feed the tree are close to the surface of the soil.

Phenology calendars are on sale for $15 at the Sauk County UW-Extension office, 505 Broadway St., Baraboo. For more information, call 608-355-3250.

Contact Phyllis Both by email at or by telephone on Monday mornings at the Sauk County University of Wisconsin-Extension office, 608-355-3253.