As I posted on another forum,I am fairly new to gardening and several years ago I was shopping for plants to fill several beds. Money was a little tight so I was pleased to find that pink dragonflowers were self-seeding.I ordered three (maybe six?) and planted them in the corner of one bed. They were very pretty. I covered the bed in the fall and when I removed the mulch in the Spring I had hundreds of two to three inch high plants growing all over. I waited until they were a little bigger so I could identify them by their foliage and it turns out they were dragonflower. I gave literally dozens away (with a warning) and threw at least that many more away. I have thrown away 75-100 this year. They apparently have a complex root system that makes it nearly impossible to remove them without damage to the surrounding plants. I find it strange that the white flowered version of this plant is said to be nowhere near as invasive as the pink. However ,I don't personally intend to find out.