Put Away Those Pruners!

by Leslie Lyles, M.S. |

Hot summer temperatures will soon be waning and many homeowners will be anxious to get their yards cleaned up before winter. Pruning is often a task that they just want to get done. Their busy work leads the homeowner to assume that fall is the time for such chores, yet many are unaware that fall pruning is actually one of the worst times to prune!

Nothing aggravates an horticulturist more than seeing many “professional” gardening companies busy pruning down shrubs, trees and grasses. Pruning stimulates growth. If pruning is done in the fall, before the plant has gone dormant, the plant will start using stored energy to produce new growth at a time when it should stop growing and go dormant. Not only does the pruning delay dormancy and increase winter injury to the plant, but it also depletes energy reserves that the plant will use in the spring to initiate new growth. Another problem with fall pruning is that many wood-decay fungi are active in the fall. And since pruning wounds are slow to “heal” this time of year, the plant is least able to defend itself from infection. In other words, fall pruning can make for some really unhealthy plants.

Now that you are aware that pruning needs to wait until late fall or early winter, you should be aware that timing of pruning is different for different plants. You could actually be robbing yourself of the beauty the plant was chosen for If you do not know what plant you are pruning. Spring flowering shrubs (such as forsythia, lilac, quince and flowering almond) should be pruned in late spring after they bloom. These plants bloom on one-year old wood; pruning in fall or winter removes the wood that would bloom in the spring. For instance, if you prune your lilac shrubs in the fall it is highly likely that you will not have many blossoms the following spring.

Spring beauty is not the only thing destroyed by poor pruning. Some plants are attractive assets to the winter landscapes; Caryopteris (Blue Mist Spiraea) have beautiful papery seed pods that brighten up the winter landscape. Ornamental grasses are also placed in the landscape for their winter interest. Most of the grasses bloom in late summer or fall, and their seed heads stand out in the bleak winter landscape. Pruning these plants in the fall will eliminate the winter beauty they provide in an otherwise barren landscape.

Before you tackle your landscape this fall, think twice about grabbing the pruning shears. Know what plants you have in your yard and what the proper timing for pruning is for each plant. If you need help, seek out the assistance of a Horticultural Consultant. You will be rewarded with beautiful and healthy plants.

References:

1. Bradley, Steve. 2005. The Pruner’s Bible: A step-by-step guide to pruning every plant in your garden. Rodale, inc.
2. Harris, Richard W. 1992. Arboriculture: Integrated management of landscape trees, shrubs, and vines. Second Edition. Prentice Hall.