How to Prune Shrubs

There are many different types of shrubs, and their pruning needs differ greatly according to their growth habits. Some shrubs are dense with thin branching and a bushy growth habit. Others may have a graceful drooping habit with thicker arching branches. Certain shrubs have a more upright growth while others tend to spread out. How to prune your particular plant will depend a lot on your personal taste and the look you are going for in your landscape. There are, however, a few tried and fast rules to remember that will keep your shrubs healthy and looking their best.

Always immediately remove damaged, dead, and diseased branches for health reasons. This can be done any time of year and is often the first step in more extensive pruning. Most flowering shrubs are pruned after the flowers fade which often occurs in late spring or early summer. This is also good time to go ahead and consider the desired shape and size of your shrub and make necessary adjustments. Suckers also can be removed any time although some gardeners prefer to use suckers as a means to propagate new plants.

Technically, there are four kinds of pruning: pinching, shearing, heading, and thinning.

However, the first two don't actually involve pruners. Gardeners commonly "pinch" annuals, using thumb and forefinger, to keep them compact. Shearing is performed on hedges with shears (a larger tool than pruners) or a power hedger. Shrubs such as boxwoods (Buxus spp.) are ideal candidates. Of the remaining two procedures, thinning is more common, so let's take a close look at how to perform thinning cuts on a shrub.

When to Prune Shrubs

Many newbies lose out on optimal floral displays from shrubs that bloom in spring on old wood, such as quince (Chaenomeles speciosa) because they pruned too late the prior year (removing flower buds in the process). Prune this type of shrub right after the flowers begin to fade in mid-spring. The exception is when you're performing rejuvenation pruning, which is best done in late winter.

Prune shrubs that bloom in summer or fall on new wood, such as beautyberry (Callicarpa dichotoma), in late winter. Floral count for the current year won't be impacted.

Avoid pruning any shrub too late in the growing season, which encourages tender new growth that will die in winter.

Before Getting Started

Begin by deciding whether to use anvil or bypass pruners.

Of the two, bypass pruners are more like scissors, except that their blades are curved. When you squeeze the handles, these two blades "bypass" each other. The result is a sharp, clean cut. Achieving such a cut isn't just an aesthetic issue: Pathogens can gain entry into a branch more easily through messy cuts. Anvil pruners are designed differently. They're not curved. They're composed of one straight cutting blade and one flat edge (or "anvil"). When you squeeze the handles, the cutting blade closes down upon the anvil. Because of this crushing action, the quality of the cut differs from that of bypass pruners. Instead of receiving a sharp cut, the green wood of a living shrub branch tends to get a bit pulverized.

Anvil pruners are fine for removing dead wood, but bypass pruners are better for pruning living wood. That's one reason why we'll be using them here; that, plus the fact that anvil pruners are bulkier than bypass pruners, making it harder to get in close for crotch cuts.