Now that crapemyrtles are going dormant, there are a few things that you might like to do at this time. If you had Crapemyrtle Bark Scale this year and you still see remnants of white encrustations, now is a good time to spray your plants with dormant oil containing paraffin wax. This can be done multiple times. Adult females on plants lay large numbers of eggs under the scale shell soon after she attaches. As eggs hatch, the young nymphs or crawlers emerge from under the female’s protective scale as they have legs and are mobile. Left solely to their own devices, movement takes place in a short distance. But these crawlers are very small and light weight and may briefly attach to insects or legs of birds and are blown in the wind to adjacent plants. This accounts for the rapid spread of this insect.
The best window for control of Crapemyrtle Bark Scale is in April or early May as the plants really flush during this time. Apply a soil drench of an Annual Tree & Shrub Insect Control. The ingredient that is most affective at this time is imidacloprid. A soil drench is placed around the root zone, specifically in the drip line of tree/bush. It’s wise to treat adjacent crapemyrtle as well even though no scale is visible. In time there will be better methods of control as this is a fairly new problem that the U.S. is now experiencing.
You can remove suckers at the bottom of the plant at this time. In fact, the suckers can be removed anytime of the year. They will certainly look neat and tidy throughout the winter months if you remove them now. Do not remove tall limbs or prune the plant at this time. Wait until early spring and do not severely prune your plant. Less is more in this particular case. In most cases you only prune in the event a branch is dead, broken or rubbing against another branch. Then you will need to take the branch going to the middle back to the main branch.
We have two miniature crapemyrtles that can be cut back within a few inches of the ground. They are meant to be bushy and not a tree size. If you ever cut a taller one back to the ground, you can retrain it by pruning out the weak branches and keep the ones that are strong and symmetrical. In time you will have an attractive tree if it’s a taller variety. The miniature plants stay small (3’ and less) and usually take very little trimming. The variety we have is called Pixie White. It’s not one that you commonly see in Oklahoma.
If the winter becomes very dry, give your new plants some extra water from time to time. About two inches of mulch will also help them during the winter months. As always, we can look forward to show stopping blooms this coming summer