Get crape myrtles off to a good start

John Young, Gill, Daniel J., Owings, Allen D.  |  2/13/2009 9:21:44 PM

Sustainable Landscape News Distributed 02/13/09

By LSU AgCenter Horticulturists

Crape myrtles are the most popular of our flowering trees, and questions abound about their proper care and cultural practices. Keys to crape myrtle success include abundant sunlight, ideal soil pH and drainage, proper pruning, regular fertilization, proper mulching and insect control.

Crape myrtles need full sun to grow the best, perform the best and bloom the best. This means eight hours or more of direct sunlight daily. Less than eight hours is not sufficient for ideal performance. Many of us underestimate the amount of sun our landscape receives. Check sun patterns in the morning, during the middle of the day and during the late afternoon.

Soil pH is important for crape myrtles but maybe not as important as it is for some of our other landscape plants. Crape myrtles like a soil pH of 6.0-6.5. This is considered slightly acid. Do not guess what the pH is – have your soil tested. You can lower pH with sulfur products and raise pH with lime products, but always do one or the other based on the test results of a soil sample.

What about pruning? February is the time to prune crape myrtles, but your particular crape myrtle may not need pruning. When it does, however, maintain its natural shape. Thin out the branches instead of hacking off the top like a buzz cut. This travesty is commonly referred to as “crape murder.” Don’t do major pruning to reduce height.

Fertilization is important. It is especially important if you aren’t following other cultural and care practices. To maximum spring growth and the resultant summer bloom, fertilize your crape myrtles in early spring just prior to new growth. A fertilizer like 8-8-8 or 13-13-13 will work fine and is recommended. It is better to place fertilizer in drilled holes in the ground (about 8 inches deep) than it is to just throw it on top of the ground. You can delay fertilizing until late spring or summer, but the trees won’t benefit as much as when you fertilize in late winter or early spring.

Mulching is, unfortunately, incorrectly done in many residential and commercial landscape plantings these days. Go “out” with mulch instead of “up” with mulch. Many times you will see mulch piled around the base of trees. Do not do this. Spread mulch out toward the end of the branches. Mulch crape myrtles with pine straw, pine bark or wood chips to a depth of 2-3 inches. Refresh the layer of mulch as needed. Keep mulch off the stem and lower trunk areas of the trees.

One of the frequent problems for crape myrtles is insect damage. Actually, insects do not do that much damage, but aphids feeding on the new shoot growth in the spring can be a problem. White flies also can cause problems. Left unchecked, these insects will release their bodily fluids onto the foliage. The resultant honeydew on the foliage leads to sooty mold on the leaves – the black discoloration that occurs normally in the early summer through fall. By controlling the insects, you can greatly reduce or even eliminate sooty mold.

Follow these practices to help your crape myrtles be successful, long-term attractions in your landscape.

Come to LaHouse in Baton Rouge to see sustainable landscape practices in action. The home and landscape resource center is located near the intersection of Burbank Drive and Nicholson Drive (La. Highway 30) in Baton Rouge across the street from the new LSU baseball stadium. Go online to www.louisianahouse.org and www.lsuagcenter.com/lyn for more information.

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Contacts:
Dan Gill at (225) 578-2222 or dgill@agcenter.lsu.edu
Allen D. Owings at (985) 543-4125 or aowings@agcenter.lsu.edu
John Young at (225) 578-7913 or JoYoung@agcenter.lsu.edu
Editor: Mark Claesgens at (225) 578-2939 or mclaesgens@agcenter.lsu.edu

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