The Plant Lady: January is the time to cut ornamental trees; here’s your guide

The end of January through February is a good time to prune ornamental trees. First, the lack of foliage allows for a much easier view of the branch structure. Second, for evergreen trees, pruning when cool prevents sudden exposure of foliage to sun and heat. Lastly, pruning close to the start of the growing season helps to heal wounds faster. However, if you have a Wisteria, Camellia or Snowball “tree,” avoid pruning them at this time. Once-blooming spring shrubs should be pruned directly after they are done flowering. The pruning instructions below pertain to true ornamental trees.

Having the correct tool is crucial for pruning. Proper tools prevent frustration and, more importantly, prevent damage to the tree. My go-to tools are hand pruners, loppers, a folding saw, a pole saw (if you have a bad neck this tool is not your friend) and in some cases a chainsaw. Make sure the blades are sharp on all tools, as a dull blade can cause tearing and ripping of bark. Disinfecting the tools before and after will help reduce the spread of certain diseases — Lysol or isopropyl alcohol make excellent disinfectants.

There are two main pruning cuts. The first type are heading cuts, where a portion of a branch is cut back to another growth point. This is done to shorten branches. Heading cuts should be made to an outward facing growth point (bud). Pruning back to a bud versus pruning midway along a branch prevents the growth of numerous branches from sprouting. Ideally, these should be at an angle to allow excess moisture to run off. The second type are thinning cuts, which are removal of a complete branch. A combination of both type of cuts is normally done during the pruning season. Try to do more thinning cuts though, as this will create the open canopy on mature trees.

For mature trees, thinning cuts should be made as close to the branch collar as possible without cutting into it. The branch collar is the doughnut-shaped structure from which a branch protrudes. When pruning a large heavy branch, a few preliminary cuts are required to eliminate the danger of tearing, which occurs when the weight of a falling branch pulls large chunks of bark off the trunk as it falls.

▪ About 2 or 3 feet away from the trunk, cut a few inches into the branch from below.

▪ About ½-1 inches out from this cut, do a second cut from above, cutting all the way through.

▪ This will eliminate the majority of the weight on the branch.

▪ Now you can do your final removal cut at the branch collar by the trunk.

Trees are able to callus and heal their wounds, but if tearing occurs or cuts are too far into the branch collar, they will have a difficult time recovering. Poorly executed pruning cuts prevent proper healing, which in turn allows possible disease and pests to take hold. Wound seal or wrap is not needed when pruned properly. In fact, even when pruned improperly, pruning seal is often not helpful. Try to avoid pruning when wet weather is projected a few days out, as this moisture can exacerbate the likelihood of disease in a fresh wound.

Trees younger than 3 years old require zero to very little pruning. All that should be done is removal of damaged/dead branches, roostock (if grafted) and noticeable crossing branches. Young trees need all the foliage they have to grow and turn into a beautiful tree. Yes, they may look gawky and gangly, but in no time they will go from an ugly duckling to a beautiful specimen if pruned diligently. Below are some guiding principles:

▪ Young trees often have a very tall leader with minimal side branching — this is normal.

▪ Avoid topping the tree, as once this has been done, it is difficult to get the structure back.

▪ Along with providing all the photosynthates the tree needs to grow, the foliage will help shade the young sensitive trunk to sunburn.

▪ After 3-4 years, start setting the scaffold branches of your tree.

▪ Remember the lowest branches of most trees are desired at 6 feet.

▪ As the tree grows, you can start eliminating lower branches a few at a time.

▪ Most of the time young trees need to be staked as well. The proper way to stake a young tree is by using two sturdy poles about 1 foot from the trunk. Tree trunks should be tied snugly, but loose enough for the trunk to move gently in the wind. This movement helps the tree build its trunk taper.

For mature trees the goal is to have an open, evenly distributed canopy. Ideally no more than 30% of tree material will be pruned at a time. Below is a basic workflow:

▪ Always remove broken or dead branches first.

▪ Second, crossing limbs should be addressed.

▪ Last, remove or prune back branches to allow an open canopy.

▪ Some branches may have something called “included bark”. This is where two branches are sharing bark and growing close together. This can cause a weak growth point, so it is best to remove one of the branches.

This story was originally published January 22, 2020 at 11:33 AM.