Crepe Myrtle Stump Removal . While it may be tempting to trim your crepe myrtles yourself, attempting the. This bush had about 6or 7 trunks growing out of the main. How to Kill Crepe Myrtle (with Pictures) wikiHow from www.wikihow.com Can you cut back a crepe myrtle in the summer? The herbicide will reach the roots from inside. Paint the stump with a glyphosate systemic herbicide with a.