Originally from China, crape myrtles are truly beautiful trees.
With their colorful flower blooms and delicate, exfoliating bark, it is no wonder that crape myrtles have become a favorite for homeowners and landscapers all across North Carolina and the rest of the South. Here at Leaf & Limb we receive numerous inquiries from individuals asking what they should do to ensure the well-being of their crape myrtles.
Here is some general information about caring for these trees:
Crape myrtles generally grow best in soil with a pH of 4.5 to 7.5.
But even if the soil conditions are not ideal, crape myrtles need very little fertilizer, since they are hardy trees. For older plants, sickly plants, or plants in especially bad soil, a light application of fertilizer (low nitrogen, no phosphorus) applied in the spring when growth begins should do the trick.
Crape myrtles thrive in full sunlight and full heat.
If your crape myrtle is planted in the shade, look for ways to increase sunlight, such as trimming nearby trees. If you are getting ready to plant your crape myrtle, choose a spot that has plenty of sun.
Crape myrtles, particularly those that are well established, are drought resistant.
Crape myrtles need a minimal amount of water and prefer well drained soil. Therefore you should avoid excessive watering.
Excessive watering, too much fertilizer, not enough sun, and too little heat can all cause a dearth of flowering.
These actions promote more vegetative growth, which results in less flowers.
Disease & Pests
Though there are a handful of resistant varieties, most crape myrtles are susceptible to mildew. This is the most common disease on crape myrtles. If there is a white or grey powder film on the leaves and flower buds of your crape myrtle, it may have powdery mildew. This is a fungal disease that causes damage by halting photosynthesis and other basic life processes of the leaves and buds, which harms the tree. It can be eradicated by applying any fungicide that is labeled for mildew on a weekly basis until the flower buds open. In addition, thinning out branches in order to allow sun and air flow penetration into the canopy can help reduce susceptibility to mildew problems.
These are yellowish green insects that can cover the underside of the crape myrtle’s leaves and cause damage by sucking sap out of the tree. In addition, they produce sticky honeydew drops that get all over the tree itself as well as nearby decks, chairs, cars, and patios. These pests are controlled by predators, such as lady bugs. But if you are using pesticides, it may be killing the predators and not the aphids. Quit using pesticides and see what happens – it should allow the predator population to grow and they in turn will eat the aphids. If that does not work, try spraying your crape myrtles with insecticidal soap, such as Safer’s Soap, or with an oil product, such as Neem Oil Spray or a paraffinic oil.
Whole books can be (and have been) written about controlling Japanese Beetle infestations. Here are some of the basics. If you are able to start early before there are too many Japanese Beetles, hand removal is the most effective control method. The best time to do this is early in the morning, when the beetles are still sluggish. The goal is to remove the beetles while they are emerging, before they have a chance to emit pheromones. Just pluck the beetles from the tree, reaching from above (so they cannot fly away) and drop them in a bucket of soapy water. A variation to this method, which can be used if a) there are many beetles or b) you do not want to touch these critters, is to simply place a bucket of water underneath a branch or cluster of flowers, then tap the branch. The beetles usually fall to the ground when disturbed and they will land in the water. Again, the early morning is the best time to do this since the beetles are generally still lethargic. Other methods include:
- Use a shop vacuum to suck up the beetles.
- Blend dead beetles with some water, then spray this on the plant. Many farmers swear this method is most effective.
- Blend garlic and hot peppers in water and spray this on the trees.
- Shower the trees with a commercial garlic spray used to deter mosquitoes. This usually works with beetles as well.
- Encourage birds to take up residence by placing birdbaths, feeders, and nesting boxes nearby. Birds, especially Starlings, love eating Japanese Beetles.
There are many other methods for getting rid of these pests, but do keep two things in mind: First, Japanese Beetle traps are a bad idea. They generally attract more beetles than they kill, which leaves an excess of new bugs to prey on your trees and plants. Second, it is usually not worth spraying Japanese Beetles with pesticides since this will also kill aphid predators and likely lead to an explosion in the aphid population.
The good news is that crape myrtles are very tough trees.
They do not need much care in order to survive. But if given a little extra TLC, your crape myrtles are sure to be especially healthy trees full of lovely flower blossoms.