Shrub Trimming Guide
This shrub trimming guide will help you learn the basics of how to care for your shrubs as the seasons change. Trimming, or pruning, is an important part of maintaining your shrubs in order to encourage the growth of foliage, flowers, and even fruit. Of course, there are nuances to trimming each type of plant, depending on the age and type of shrub you have and the changes you intend to make. However, there are some basic guidelines for how to go about trimming your shrubs.
When to Trim & Growth Habit Basics
Generally, the best time to trim depends on how fast your plants grow and when or if they flower. Here is a quick seasonal guide to knowing what to trim and when:
- January to March: anything young or slow-growing, and summer blooming shrubs.
- April to May: spring flowering shrubs, needle-leaf and broad-leaf evergreens.
- June to August: overgrown or neglected deciduous flowering or fruit shrubs, and faded flowers on summer blooming plants, needle-leaf and broad-leaf evergreens.
- September to October: prevention of limb breakage only.
- November to December: perennials and shrubs that die back over winter.
- Dead or diseased wood should be pruned out immediately in any season.
Shrubs have three types of growth habits: mounding, cane, or tree-like. Those with mounding habits are usually used in mass planting and have soft, flexible stems and small leaves. Shrubs with cane habits spread by sending up erect new branches called canes from their base. Tree-like shrubs have woodier, more finely divided branches. Generally, all shoots grow outward from their tips. Once those tips are removed, lower buds are stimulated to grow. Buds are located at nodes, an area at which leaves are attached to twigs and branches. Each node produces around one to three buds, depending on the species of shrub.
Heading & Thinning Cuts
Heading cuts stimulate growth of buds, whose growth direction is determined by the position of the top remaining bud. Make heading cuts to reduce shrub height and retain natural form by trimming 1/4 of an inch above the bud, sloping down and away from it. If you don’t make your cuts selectively, they may stimulate rapid re-growth from buds below the cut, which can make your shrubs bushy. You should only do this when you are using hedge clippers on a hedge or topiary. When pruning above a node with two or more buds, only remove the inward-facing ones.
Thinning cuts remove branches at their points of origin or attachment, which will reduce shrub density without stimulating re-growth. To make thinning cuts, trim just above parent or side branches, roughly parallel to them.
General Shrub Trimming Tips
- Disinfect trimming tools between each cut with rubbing alcohol or disenfectant.
- To reduce the height of shrubs with a cane habit, remove the tallest canes by cutting near ground level and thin out canes that are crowding the center.
- For height maintenance of mounding-type shrubs, trim only the longest branches. Make thinning cuts inside the shrub mass to where they will not be visible so you will not sacrifice the overall shape of the shrub.
- Tree-like shrubs are especially difficult to trim, but can tolerate removal of an eighth to a quarter of their branches.
