When trimming back a Crepe Myrtle tree that has been trimmed before, do you have to cut the limb above the "knot" area that has established from previous trimmings, or can you cut back below the "knot" area to keep the tree from growing taller each year?
Trimming Crepe Myrtle Trees
Certified GKH Gardening Expert
You should be able to, but without knowing the exact shape of the tree, we would not be able to tell you how this would affect the future shape of the tree. It would be worth it to have a landscaper who is experienced with crepe myrtles come and look to make sure that the tree will retain a pleasing shape if this sort of pruning is done. This article should help you with that: https://www.gardeningknowhow.com/ornamental/trees/crepe-myrtle/pruning-crepe-myrtle-trees.htm