What is the most popular summer-blooming tree in Louisiana? Crape myrtles. Pretty easy question. Many crape myrtles are planted in our landscapes every year. The lovely, long-lasting blooms make them attractive. Most years, crape myrtles start blooming between mid-May and early June. Flowering continues for 80-100 days depending on the variety you have planted.
You will sometimes see crape myrtles not blooming well. Why? you might ask. There are several reasons. Here are some ideas to consider.
- How much new growth did your crape myrtles have this spring? Crape myrtles need to have new growth each spring. If your crape myrtles did not produce much new spring growth, they will not have many summer flowers. Crape myrtles make flowers on the current season’s growth, so late winter/early spring fertilization can aid crape myrtle flowering in the summer. It is not too late to fertilize this year if you did not do so earlier.
- Shade issues. Crape myrtles require 8 hours of direct sun daily to bloom well. Many times crape myrtles are planted in areas that receive 4-6 hours of direct sun or less – this is not enough for adequate bloom development.
- Variety. Some varieties don’t flower as vigorously as others. The hybrid crape myrtles usually flower first. Natchez, Tuscarora, Basham’s Party Pink and Muskogee are the earliest-flowering varieties. Semi-dwarf varieties (Tonto, Acoma, Sioux) follow a week or two later.
- Insects. Heavy infestation of aphids decreases flowering. This is the most common insect problem on crape myrtles. Ever feel like you are being “rained” upon when you are under the canopy of a crape myrtle? That “rain” is actually bodily fluid being excreted by aphids. You can also have white flies and other insect issues on crape myrtles.
- Improper pruning. Drastic pruning or pruning after new growth in the spring can delay summer flowering. Drastic pruning may promote excessive growth and less flowering. Sometimes conducting the “crape murder” method of pruning on crape myrtles can initiate too much vegetative growth at the expense of flowering.
- Too much fertilizer. Excessive fertilization, especially high amounts of nitrogen, in conjunction with other factors, primarily improper pruning, can eliminate or delay flowering.
- Leaf spot. Foliar diseases decrease plant vigor and flowering, especially where new growth is not produced in the spring. The main leaf spot infecting crape myrtles is the fungus Cercospora.
- Wet soil. Crape myrtles need well-drained areas to grow well. Lichens growing on bark is common on crape myrtles growing in shady areas accompanied by poorly drained soils and low levels of native soil fertility.
So, that is the list. Hopefully, your crape myrtles will bloom and bloom some more for you this summer. Consider these ideas if you have crape myrtles not performing to their potential.