id a large debris burn im my gravel driveway and the next year every single plant inside and outside the burn area returned My entire 150' drive is covered in knapwd. Round up or vinegar? It's impossible to even begin pulling out of 6" of gravel. This was an abandoned property for 15 years so it has been entirely overrun. I can pull some but Im limited by disabilities. A full acre of that monster is overwhelming me
If it has already become invasive, then this will be a problem for professionals to handle. It would take a dangerous amount of chemicals and years worth of agricultural management to return this plot to a usable state. I would contact your local extension service for inquiries regarding invasive species control after infestation.
This link will help you to find the closest extension to you: