Replanting After Killing Weeds

Question

Started to germinate gardenia seeds yesterday to plant as a fence line but now I realize that I will have to clean up the roots of trees I dropped 3 years ago when I cleared my land (some roots are still alive). I also have some johnson grass and a few other things growing. I suspect I will have to sawzall the tree roots and physically remove them, but is there a chemical on the market I can use to kill the rest of the vegetation and still plant my potted gardenias in the same soil in a couple of months?

Answer 1

This article should help you with that: https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/how-long-does-weed-killer-last-in-the-soil.htm