Archive for Thursday, February 16, 2006

Time’s right to prune

February 16, 2006


From time to time our hair becomes a bit too wild and unruly. And all that is needed to tame the curl is a stylish haircut. In the landscape, plants often find themselves in the same situation. But instead of heading to the barber shop or beauty salon, sharp pruners, a watchful eye and knowledge about plant bloom time are all you need to become a pruning pro. Here is what you need to know about pruning shrubs to help prepare them for the upcoming spring show:

Often times, gardeners approach pruning with uncertainty and many questions. However, it is not as difficult as it may seem. Begin with the fact that not all shrubs can be pruned this time of year and that deciduous shrubs are pruned differently from evergreen shrubs.

Deciduous shrubs are those that drop their leaves, and evergreens maintain green foliage. Likewise, deciduous shrubs are placed into one of three groups: those that flower in the spring on wood produced last year; those that flower later in the year on wood that was produced this spring; and those that may produce flowers, but the blooms are of little ornamental value to the plant.

Next, ask yourself: "Why am I pruning?" Shrubs are pruned to maintain or reduce size, rejuvenate growth, or to remove diseased, dead or damaged branches. This process, called thinning, is used to thin the canopy of plants that are too dense. To thin the shrub, remove most of the inward growing twigs by either cutting them back to a larger branch or cutting them back to just above an outward facing bud. On multi-stemmed shrubs, remove about one-third of the oldest, thickest canes as they have few blooms and leaves.

A little more severe pruning is called heading back. Heading back is used to either reduce the size of the shrub or keeping the plant more compact and in bounds. It is accomplished by removing the end of a branch by cutting it back to a bud or the next major branch. Branches are not cut back to a uniform height, helping to maintain the unique growth pattern of the plant.

Finally, there is rejuvenation pruning - the most severe type of pruning. It can be used on multi-stem shrubs that are too large and have too many old branches to justify saving the younger canes. All of the stems are cut back to 3- to 5-inch stubs. This is not recommended for all shrubs but does work well for barberry, red twig dogwood, privet, spirea, forsythia, pyracantha, ninebark, Russian almond, little leaf mock orange, shrub roses and flowering quince.

With all of that said, shrubs that flower on new wood and shrubs planted for their foliage, and not their bloom, can be pruned now. Examples of these include Annabelle and Peegee hydrangeas, Anthony Waterer spirea, shrub dogwoods, barberry, burning bush, smokebush, sumac, ninebark and purpleleaf sandcherry plum.

Shrubs such as mock orange, potentillas, roses and weigela that flower later in the year, on new and old wood, can be lightly pruned now before growth starts or heavily pruned after blooming has ended later this spring. Contrary to this, now is not the time to prune spring-flowering trees and shrubs. Plants such as lilac, forsythia, azalia, rhododendron, magnolia, flowering dogwood, chokecherry, flowering plum or cherry, and Juneberry all bloom on old wood. Pruning now will remove the existing dormant buds, thus decreasing the floral display this spring. All of these should be pruned once blooming has ended.


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