The Best Time to Prune Trees and Shrubs

By Christina Timm

Things to Consider Before You Prune Back Trees and Shrubs

There have been a lot of questions about the best time to prune back trees and shrubs. There are two factors that determine the best time to prune: 1.) If your tree or shrub blooms and if it does 2.) when does your tree or shrub bloom? There are exceptions to the rule so be sure to do some research or call 763-420-4400 and ask Donna before you prune.

General Rule for Pruning Trees and Shrubs

Spring blooming tree or shrub: If your tree or shrub blooms in the spring time, it is best to prune when the flowers are done blooming and have faded.

Summer blooming tree or shrub: If your tree or shrub blooms mid to late summer, it is best to prune during the winter while the plant is dormant, or early spring before it blooms.

Tree or shrub that does not bloom: If you have a tree that does not bloom at all, it is best to prune during the winter while it is fully dormant, or any other time other than Fall.

Do Not Prune Any Type of Tree or Shrub in the Fall.

Fall is never a good time to prune. Any time you prune a plant its natural reaction is to produce new growth. If this happens in the fall the plant will not harden off properly and will have trouble going into dormancy. This can cause problems in the spring and can even cause problems coming back.

For Trees: Dead branches should always be removed as soon as possible.


Hydrangeas

When thinking about pruning a Hydrangea shrub there are two things to think about: 1.) what time of the year to prune and 2.) how much to prune back. Just like with any other tree or shrub it’s important not to prune back the foliage in the fall

20180509_105538.jpg

So, when is the best time to prune a Hydrangea?

The best time to prune for a Hydrangea is right after it blooms, and the flowers start to fade. Something you may not have known is that blooming plants start forming their buds for spring the fall beforehand. So, if you wait too long to prune, there is potential that you are reducing your amount of spring buds. The absolute latest you can prune your Hydrangeas is August 1st. This way you can ensure you are not cutting away any buds that will become spring flowers.

So how much do I prune back?

For Hydrangea shrubs it’s important not to prune the entire shrub back! Some hydrangeas bloom on existing wood. This means new blooms emerge from old wood. If you prune back a Hydrangea shrub to the ground removing the old wood, you are also removing any new buds for its next bloom time. Not all Hydrangeas bloom from existing wood, but it is still recommended not to completely hack down the shrub. Play it safe; for any Hydrangea wait until the flowers have faded and then remove the flower head to about 12-20” down.

Garden Tip: Cut Hydrangea flowers can be hung upside down to dry out and then used in spruce tip arrangements for the holidays.


20180509_151046.jpg

Roses

The best time to prune newly planted Rose Shrubs is early spring. So just after spring’s final frost and after the plant breaks from dormancy prune roses back. Also, you should never be pruning your roses down to the ground unless there is severe damage, dead wood, or disease. Most established Rose shrubs can handle a harsh pruning, cutting 1/2 to 2/3 of the shrub’s height. This helps older shrubs rejuvenate by removing old, woody stems.

Lilacs

The best time to prune a Lilac shrub is right after the flowers turn brown. Lilacs are early bloomers and they set their buds early for the next year. This means any pruning in June or later in the season takes away any new bud formation for the following year. Most Lilacs don’t need any pruning until they reach about six to eight feet tall.

Learn the difference between freeze and frost.