Pruning is one of the most controversial issues amongst gardeners, as well as one that consistently comes with two questions: how and when does pruning happen? First, it’s important to understand why we should prune our plants. Then, we are going to talk about when to prune different types of trees and shrubs. Finally, we will discuss how to properly prune or cut back your plants.
There are two main reasons for pruning and cutting back your plants: 1. To remove diseased, dead, or decaying branches. Depending on how bad it is, the affected branch could cause more harm to your plant or attract insects or diseases. If you are looking at a tree, dismissing diseased, dead, or decaying branches could also put your home or other nearby buildings in harm’s way. 2. Pruning promotes new growth and encourages fruitfulness/flowering.
SPRING BLOOMING SHRUBS
Shrubs that bloom in the spring typically grow on old wood. In other words, buds begin to form on branches throughout the summer and fall before the shrub flowers. If you want to have blooms the following year, you need to prune these shrubs after they are done blooming for the season.
Some spring flowering shrubs include: lilacs, deutzia, azaleas, spirea, fothergilla, ninebark, kerria, mockorange, weigela, forsythia, viburnum, st. johnswort, red twig/yellow twig dogwood, and two types of hydrangeas (macrophylla and oakleaf).
SUMMER BLOOMING SHRUBS
Shrubs that bloom in the summer typically bloom on new wood. In other words, the buds begin to form on branches throughout the spring before it flowers. Therefore, if you want to have blooms during the current year you need to prune these shrubs in late winter.
Some summer flowering shrubs include: carolina allspice, rose of sharon, smoketree, sweetspire, two types of hydrangeas (paniculata and arborescens), butterfly bush, and sweetshrub.
Although there are a few exceptions, the very best time to prune a majority of trees is during their dormant stage; after leaves have completely fallen off. Anytime between leaves being off and buds beginning to appear is considered ‘dormant.’ Trimming or pruning at other times leaves trees susceptible to insects and diseases of all sorts.
There are, however, a couple of exceptions for pruning trees in the spring. If you must, remove dead, decaying, or diseased branches for the safety of your tree and/or home.
Some trees will need pruning as soon as they’re done blooming: apricot trees, chokecherry, crabapple, dogwood, flowering cherry, flowering plum, juneberry, magnolia, and lilac trees.
There are a few trees that you never want to prune in spring, summer, or fall: oaks, elms, sycamores, and honey locusts. When these are pruned outside of dormancy, the risk for infection, disease, and insect damage grows significantly.
Now that you know when to prune, we will share important steps to take when pruning your shrubs and trees.
Make a Plan
Know what your goal is before you start cutting branches off!
Remove dead, diseased, or damaged branches
If a branch is diseased, be sure to cut back several inches below visible symptoms
When you finish with diseased branches, ALWAYS disinfect tools so you don’t spread the disease!
Remove crossing, rubbing, or misdirected branches
They will rub open “wounds” into the branch which will, in turn, leave your shrub vulnerable to insects and disease
Stop and Repeat Step 1
Have you reached your goal? Has your goal changed?
How much was removed? - Do not remove more than ⅓ of the shrub at one time.
Shape your Shrub
DON’T do this first!
Make clean cuts - ragged cuts are very bad for your shrub
Using bypass pruners (shown below) will help make this easier to accomplish
Make a Plan
Mark which branches you want removed
Biggest cuts first
Cut in increments to prevent tearing
Cut back to lateral branch
Saw thick branches in 3 cuts
Make 3 cuts on any branch 3 inches (or bigger) in diameter
Start approx. 6” from desired cut in order to reduce tearing
Cut off stub (from Step 3)
Cut at a 45* angle
Remove suckers at the base of your tree
Take care not to nick any bark on the trunk
Clip water sprouts
These are little shoots that grow straight up and can crowd the tree and block proper sunlight and air circulation on the inside
Remove inward growing or rubbing branches
Every branch it touches will be wounded from rubbing
As with all your plant, garden, and landscape questions, we are here to help! All the information in this blog post follows a ‘rule of thumb’ mentality. If you have any more questions about pruning your trees and shrubs don’t hesitate to reach out to us!
For more information on pruning, contact your local Green View: