Same for me, Zuzu, until suddenly last summer I realized the plant I'd been cutting back for two years that kept reappearing was a crape myrtle. I have no idea where it came from but persistent as it was, I just gave it that part of the bed and moved on to the back yard container for the hospital. Everything that had so carefully been planted in it died from the drought, so I really thought it had become a plant graveyard until all those ailing plants took on new life a couple of months ago and the back yard container is really crammed full now.
Never a dull moment in a garden.
