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DALY: Proper pruning helps keep plants healthy and attractive

Proper pruning helps keep plants healthy and attractive

One of the most important cultural practices for maintaining woody ornamental plants is pruning.

Pruning is the process of removing plant parts to improve its shape, to reduce plant size, and to remove damaged or diseased sections. Each plant species in the landscape has its own growth habit and specific pruning requirements. Some shrubs have slower growth habits and may never need pruning while vigorous shrubs may require frequent attention. Unsightly plants often result from not pruning or incorrect pruning.

Proper pruning requires a basic understanding of how plants respond to pruning. The terminal bud on the end of the branch secretes a hormone that suppresses the growth of the lateral buds. When the terminal is removed, the lateral buds and shoots begin to grow. The most vigorous new growth occurs a few inches below the pruning cut.

Often, a shrub is pruned by shearing the new growth to control its size and shape. However, the continual shearing results in dense, thick, new growth being produced near the outer portions of the canopy. Less light reaches the interior portions of the plant, leading to sparse foliage with a leggy or hollow appearance which can increase the risk of harm from environmental stresses and pests. Thinning is a pruning method involving the selective removal of an entire shoot or limb to its point of origin on the main branch or lateral branch. Thinning cuts shorten the branches, improve light penetration and direct the growth of shoots or limbs. It encourages new growth within interior portions of a shrub, reduces the plant size and creates a more attractive plant.

Frequently a shrub is overgrown, and it needs to be heavily pruned. Late February into March is the best time of the year for this task. As the weather warms up, the plants will have a huge flush of growth that will quickly cover the bare branches. Avoid renewal pruning in the fall or winter, which will cause the shrubs to have an ugly, bare appearance until the new spring growth occurs. Most broad leafed ornamentals, such as ligustrums, hollies, crape myrtles, and cleyera, respond well to renewal pruning. However, boxwoods recover slowly and can die when subjected to severe pruning. Narrow-leafed evergreens, such as junipers, Leyland cypress, and arbovitaes should never be pruned in such a manner since they do not regenerate new growth from the old wood and could perish.

The best time to prune varies with plant species, and should be done at times that complement the growth characteristics, flowering, and other objectives you desire. Prune spring flowering shrubs, such as forsythias, flowering quince, and azaleas after flowering since pruning before flowering will remove the flower buds. Summer-flowering plants, such as vitex (chaste tree), tea olive, roses, and crape myrtles can be pruned in the dormant season since they flower on the new growth.

Pruning plays an important role in the development and maintenance of woody plants. The development of clear pruning objectives is important, and by combining them with a basic understanding of pruning and the response of plants to it, you can get the results you desire.

Winter is a good time to decide on what to plant in your yard. The Gwinnett County Extension annual plant sale has some excellent plants that are available for sale. If you are interested in purchasing some of these excellent plants, go online to the Extension website at www.gwinnettextension.com, click on events to download the order form or call the Gwinnett County Extension office at 678-377-4010 for one to be mailed to you. The deadline for ordering is March 12. The order pick-up day will be March 21 from 10 a.m. to 6 p.m. at the Gwinnett County Fairgrounds, 2405 Sugarloaf Parkway, Lawrenceville, Ga.

Timothy Daly, MS is an Agricultural and Natural Resource agent with Gwinnett County Cooperative Extension. He can be reached at 678-377-4010 or timothy.daly@gwinnettcounty.com.