I have a couple jobs with beds that have a ton of trees(seedlings) coming up. And a job we cleanedup and cut alot of scrub growth down. What is good to use to kill this stuff. I've sprayed roundup but no success. The job with scrub growth looked like a forest before and now alot is returning. only way to get rid of it is to dig it out but theres so much plus they dont want to spend the money. Please Help!