By LSU AgCenter Horticulturists Dan Gill, Kyle Huffstickler and Allen Owings

Proper pruning is one of the most neglected and misunderstood of all gardening practices, yet it is one of the most important best management practices in a residential or commercial landscape when done properly.

Pruning is a skill and an art. It is a skill in making cuts that properly heal or callus over to seal off the wound from disease and infection and an art in making the right cuts in the right places to get the plant to take on a more pleasing form. Pruning should be practiced as a vital part of the maintenance program for all shrubs and trees. Most shrubs will require some pruning annually and may require special attention to correct defects caused by mechanical injury or attack by insects and diseases.

Important items to consider prior to pruning include:

– Your goal in pruning.

– The method that will be used (natural vs. formal).

– The ideal time of year to prune this plant.

– How flowering or other plant performance may be affected.

– How this particular plant responds to pruning.

Why prune? Pruning is done to remove dead, diseased, dying or decaying wood. Sometimes we refer to this as the four Ds of pruning. You also can prune to manage plant size and maintain a particular form for design specifications. Pruning, in some situations, can be done to rejuvenate old plants.

Pruning flowering shrubs depends on the times they bloom.

Prune late-winter- and spring-flowering shrubs after they flower. If spring-flowering shrubs are pruned during winter, you’ll be removing flower buds. Examples in this category include azalea, spirea, mock orange, quince, hydrangea, weigelia, forsythia, gardenia, camellia, viburnum, deutzia and flowering almond. Azaleas that flower in spring need to have pruning completed by late June or early July in order not to affect the flower buds being developed for the next spring.

Summer-flowering shrubs are pruned from mid- to late winter, before spring growth. Some plants in this group are crape myrtle, oleander, vitex and althea. Most evergreens not planted for their flowers should be pruned in the dormant, winter season, but some pruning may be done throughout the year.

No rules cover all pruning. The important consideration should be preserving the natural form of a particular species. The extent of annual pruning will depend on the plant. Some shrubs may require the removal of a considerable amount of wood each year, while others require little pruning. It is much better to prune lightly each year rather than severely butcher a plant after several years of growth.

When pruning, first remove weak and spindly wood inside or near the ground. Next reduce the height of the plant to the desired level by making cuts at various levels, always keeping in mind the natural form of the plant. One rule for cane-type plants like nandina and mahonia is to remove one-third of the oldest and tallest canes near the ground each year. This will keep the height of the plant at a reasonable level.

Several special plant types or categories need special treatment for specific training purposes. These include espaliered plants, topiary or “poodled” plants and other landscape oddities. These may need to be pruned on a more regular basis to maintain the intended growth form.

Visit LaHouse in Baton Rouge to see sustainable landscape practices in action. The home and landscape resource center is near the intersection of Burbank Drive and Nicholson Drive (Louisiana Highway 30) in Baton Rouge, across the street from the LSU baseball stadium. For more information, go to www.lsuagcenter.com/lahouse and www.lsuagcenter.com/lyn.

Rick Bogren