A: These sprouts growing around the base of the crape myrtle are called suckers. If you leave them they will eventually become large making the tree have more trunks than desired. We would suggest limiting the crape myrtle to no more than five main trunks with three to five being acceptable. This makes the tree much easier to manage.
It is appropriate to prune suckers from any tree any time of year. Removing them early, while the stem is small, is the preferred practice. Remember anytime a pruning cut is made there is the potential opportunity for decay to occur. Therefore, removing the stem when it is small minimizes the possibility for disease. No need to paint the cut with any substance. Allow the natural ability of the tree to seal over the pruned area.
Several pruning sessions may be required to control suckers from forming but eventually fewer and fewer will be produced. You may also remove any dead or decaying branches any time of year. Stems rubbing each other, those growing straight up from a branch (water sprouts) or those growing toward the trunk should also be pruned.