Asked February 23, 2021, 10:13 AM EST
Harford County Maryland
In general crape myrtles grow best in full sun in a well drained soil. They do not demand a lot of fertilizer.
Older varieties of crape myrtles (including varieties that were available in the 1980s) are more susceptible to fungal diseases including powdery mildew and Cercospora leaf spot. Newer cultivars are bred with disease resistance. Look for resistant varieties.
Also, crape myrtles can be marginally hardy especially if we have a cold winter, frosts, or are planted in a windy area. Some branch dieback can be expected.
Depending upon the cultivar and environmental and site conditions, they may be susceptible to aphids, a sucking insect.
Here is a link from Clemson for more information https://hgic.clemson.edu/factsheet/crape-myrtle-diseases-insect-pests/
Crape myrtles require little to no pruning. The type and amount of pruning depends on the desired shape and size of the plant. There are many types of crape myrtles which include low shrubs to 30 foot tall tree types. They should be pruned to remove unhealthy branches, to remove suckers, and to allow more air movement in the tree canopy. The time frame to prune is early spring as they bloom on the current season’s growth.
As mentioned, it is not necessary to prune crape myrtles, but we see others doing so and feel obliged. This happens so often severely that it has a name: crape murder.
The best way to maintain a crape myrtle at a particular size is to plant a known cultivar that will mature at the desired height and spread. For more information on pruning see the following links:
Clemson Cooperative Extension http://www.clemson.edu/extension/hgic/plants/landscape/trees/hgic1009.html