I moved into my home about two years ago. The previous owner began as an avid gardener, but she became disinterested and stopped spliting her plants.
What I'm left with is spiderwort that has actually, somehow gone to seed (our nursery man says it doesn't go to seed, but he hasn't seen my yard!). It is in every garden in my yard, actually growing in my yard, and it's also invading my neighbors yeards and gardens. I've dug out hundreds of plants, but to no avail, they're actually new plants in my gardens now, in September! I don't want to have to use harsh chemicals because the reason I want to get rid of them is that they're choaking my roses, lilies, daisies, etc. All the information I've found says how lovey they are...any ideas on stopping/killing them before my gardens become pastures of cow slobber

Thanks!