4 Pruning Practices You Can Ignore

How to Not Kill Your Tree or Shrub with Pruning

Pruning shears
Jill Ferry Photography/ Moment/ Getty Images

There is probably nothing that puts fear and trepidation into the gardener's soul more than pruning trees and shrubs. We all start off afraid we're going to either prune it into an ugly, contorted mess or worse, kill it outright.

It would be nice if we could only plant trees and shrubs that need no pruning at all, like evergreens. But in reality, ornamental trees and shrubs need yearly maintenance to keep them constantly renewing themselves and looking and growing their best.

We've all heard that you should prune trees and shrubs that bloom I summer or later in the season in early spring and to hold off pruning the ones that bloom in spring, until after they have flowered. However sometimes you have to break these rules, whether because of damage, neglect, construction or other demands on your time. Don't worry, your tree or shrub will be able to handle it. Just don't try to make up for years of neglect in one season.

Here are 4 more pruning tenets that you can ignore.

Pruning trees and shrubs at the wrong time can kill them

It's very hard to kill a plant with pruning. You may lose the flowers for that season, but eventually it will resume its normal cycle. There are optimum times for pruning different plants, but it has more to do with things like when the plant is dormant or actively growing, when it might bleed sap, like maples and peach trees, and when it sets its flower buds.
While there are optimal times to prune woody plants, if you must do some pruning for access or to remove damaged branches, you can do so at any time of the year and not kill the plant.

A severe pruning in the spring will mean you won't have to prune again all summer.

It can be tempting to hack back over grown shrubs in spring, before they leaf out and you can see all their branches.
Unfortunately, hard pruning often stimulates new growth and lots of it. Since much of this growth will be thin, weak wood, you will have to do some thinning or it will die off on its own and cause a whole new set of problems. Severe pruning can also lead to suckering, which will require even more pruning.

It's better to do a little maintenance pruning each year. A general rule of thumb is to never remove more than 1/3 of the shrub or trees woody growth. That way you always have 1 and 2 year old branches and new wood filling in. It will keep the tree or shrub well-shaped, a manageable size and constantly renewing itself.

Prune an ailing tree or shrub to rejuvenate it.

While it's fine to prune out branches that are obviously infected or infested, putting more stress on an ailing tree is not recommended. It only forces the plant to put forth more effort growing and the new growth that it spurs will likely be more susceptible to problems. Instead, try and fix whatever is making the tree struggle, whether it is a pest, a disease, or a cultural problem. Once the tree or shrub has regained some vigor, you can resume maintenance pruning.

Seal off wounds or cuts with tree sealer, tar or pruning paint.

This was considered a good practice for a long time.
The theory was that it would prevent insects, diseases and moisture from getting inside the wood. But woody tissue has its own mechanisms for sealing over wounds and our efforts just get in its way. Sealing a wound can even seal in moisture and cause the stem to rot. If the wound was a rough tear, you can go ahead and make a clean cut. Otherwise, just let the tree or shrub heal itself.

One final note, it will be much better for you and your trees and shrubs if you keep your pruning tools clean and sharp. You don't want to pass disease problems from one shrub to the next. You also don't want to tear and damage your trees and shrubs or your hands.