Q: Several years ago I put down rolls of weed barrier under my flowering cherry and then covered it with black wood mulch. Since that time the barrier has become covered with black dirt, mulch and weeds. Roots from the tree have grown through the plastic. Should I pull up everything now? 

A: It is because of your situation that I rarely recommend landscape weed barriers. They inevitably get tangled in roots from above or below or both. They also interfere with air, water, and fertilizer movement in the soil. Do the best you can to pull out all of the plastic. Cover the soil with fresh mulch but no more weed barrier.