Are you suppose to cut dead crepe myrtle heads off?
Are You Suppose to Cut Dead Crepe Myrtle Heads Off?
Certified GKH Gardening Expert
You can remove these if you want or leave them. Either way is fine and will not cause any issues with the tree. If you choose to take them off, these articles should help with pruning: https://www.gardeningknowhow.com/ornamental/trees/crepe-myrtle/pruning-crepe-myrtle-trees.htm