Pink Evening Primrose is aggressive in my garden, but I like it anyway. It fills in gaps between other, larger perennials nicely, but I do have to rip out a lot if planting something new. However it did make me pause when it jumped to another bed! I think it was a stray seed, but I'm watchful.
Goose Neck Loosestrife was the major thug for me, still fighting with it, but have most removed.
