Pruning Ornamentals Keeps Your Garden on the Cutting Edge

Every year, landscape gardeners should step back, look at their plantings and formulate a pruning plan that will keep ornamentals looking their best.

Pruning should start as soon as you have the plants in the ground. You can shorten long stems and encourage branching to increase the density and volume of new plants.

Most landscape plants should be lightly pruned every few years. If you prune hard every year to keep a plant to a certain size in your landscape, it's better to replace that plant with one that has growth characteristics better suited to the site.

All gardeners should understand the difference between pruning and shearing.

Pruning. Pruning means individually selecting and cutting specific branches or twigs. Larger pieces are removed at specific locations on the plant.

Shearing. Shearing removes one to two inches of growth from the entire plant by indiscriminately clipping all twig ends.

Before pruning, consider the properties of the plant. Look at its natural form, growth habits, growth rate, height, spread and flowering time.

Gardeners should prune if:

• There are any dead, diseased, damaged or insect-injured parts.
• There is a need to make the plant less dense or open the center for light and air flow.
• The plant needs rejuvenation.
• A special shape is desired, as with hedges or topiaries.
• Dead flower clusters and seed pods must be removed.

Savvy gardeners should use one of three pruning methods.

Rejuvenation. This is the most severe pruning method. Used on older plants that have grown too large or woody. This approach removes the oldest branches at or near ground level, leaving only young stems. Pruning old wood on shrubs will stimulate the growth of new wood.

If there aren't many young stems, remove about one-third of the older wood each season over three years. New growth will have to be pruned to encourage some branching and to retain the quality and density of the plant.

Thinning. These pruning cuts are done by removing entire twigs or branches where they attach to the main stem. It is the least conspicuous pruning plan. By cutting the inward-growing twigs, the remaining growth will fill in the outside of the plant. This method is best used on very dense plants.

Heading Back. This method reduces the height or size of the plant. Branches or twigs are cut back to a bud or emerging side branch. The shape of the plant is controlled by the location of the bud at the end of the cut. An inward-pointing bud will make the plant denser; an outward-pointing bud will do the opposite.

Remember that heading back stimulates the development of smaller shoots and dense growth, particularly if every branch is headed back. Heading back just 30 percent of a plant's longest branches in a growing season is recommended.

Shrubs that flower in the spring should be pruned after they bloom. Plants that flower in mid-and late summer should be pruned in the spring before growth starts. Any fall pruning should be done after the plant is dormant, but keep pruning at this time of year to a minimum.

Source: Penn State Agricultural Information Services

Spring 2001
Finding the Best Site for a Garden Is More Than a Random Process | Build a Raised Bed | It Takes a Kernel of Skill to Grow Great Sweet Corn | Pruning Ornamentals Keeps Your Garden on the Cutting Edge | Lawn Care Calendar | Hort Shorts | Hort Tips | Mad Cow Disease | Green Eggs: The Science of Egg Cookery | Concern for Egg Safety | New National Standards for Organic Food | Your Spring Vegetable Garden Plan | Health & Household Tips | Did You Know?

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