As pretty as these little purple flowers are, they are the bain of my garden existence. Not only do they attract bumble bees which send me running into the house but they take over EVERYTHING! I pulled them up one year after I planted them many years ago and they still pop up all over my yard. Because they're vines, if I don't pull them up quickly they literally take over everything and I have to untwine and clip them out of my rose bushes and whatever else they've invaded. Still, they did make for a pretty picture before I pulled them out of my gladiolas.