Sharpe's Point

Kenny Sharpe

The crape myrtle is a very popular summer flowering tree that has been planted extensively for years.

Some of the endearing characteristics of crape myrtles would be the vast array of sizes, shapes and colors they provide. There are numerous varieties available with characteristics to meet most people’s needs.

Many people believe that you have to go in and prune crape myrtles annually to control their growth and make them bloom. That is not necessary. It is, however, important to select the right variety for the size you need.

Crape myrtles come in a wide range of mature heights. You can purchase short crape myrtles that will only achieve a mature height of 3 feet, such as Chickasaw or Cherry Dazzle. You can also select varieties such as Natchez or Muskogee that would mature at 25-30 feet.

Crape myrtles also come in various colors. It is important to pick the colors that go with your landscape theme and not just the colors that you like. You can find reds, pinks, lavenders, purples and whites. There is just about any shade of these available colors imaginable.

I often get the complaint that crape myrtles do not bloom properly. There are three basic problems that prohibit blooming.

First, they need sunlight. Many people overlook the tree’s basic need for light. Plant crape myrtles in full sun. Without sun, they cannot make the energy necessary to flower properly. I also see a lot of landscapes that have matured and shade has become a problem. Your crape myrtles may have once been in full sun and bloomed properly, but now the neighbor’s trees — or your own — have shaded them out.

Next, the crape myrtles need annual fertilizer applications to make them prolific bloomers. A general tree fertilizer application in spring should be adequate. You will produce more foliage and more blooms if you are fertilizing.

Finally, disease and insects can take their toll. You must have good foliage to convert the sunlight to energy for flower production. The most common problem I see is sooty mold, which is the black scaly covering on the leaves and twigs. It is really an insect problem, usually aphids, though it could also be scales or whiteflies.

These insects will secrete a high sugary substance called honey dew. The sooty mold lives in the environment and will attach itself to the honey dew. In order to get rid of the ugly sooty mold, you have to get rid of the insects.

There are several ways to prevent sooty mold. One method is to use an insecticide known as acephate. You can purchase the product as Orthene 75S or Acephate 75S, which is a soluble powder. Mix four parts (Tbsp) of the powder with one part (Tbsp) water and make a paste. Paint the paste around each trunk of the crape myrtle close to the base of the tree. The band should be twice the diameter of the trunk.

The acephate is a systemic insecticide and will travel to the leaves. When the insects come to suck the plant juices, they will be controlled and you will not get sooty mold.

I would put the first application out now until early May and then repeat the process in late July for year-round control.

Crape myrtles add summer color to the landscape with a blooming season that can last from 70-110 days, depending on the variety. 

Kenny Sharpe is the county agent with the LSU Cooperative Extension Service in Livingston Parish. For more information on these or related topics, contact Kenny at (225) 686-3020 or visit www.lsuagcenter.com/livingston.

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