Hi. I just moved into a rental property in South Delta, and the landlord has given the go-ahead to convert the totally suburban backyard into a garden. When we pulled up sod for a bed near the cedar hedge, we discovered one area with black plastic beneath the sod. When we pulled up the black plastic, it revealed an area of fairly large root network, presumably belonging to the hedge. These roots are up to 1.5 inches in diameter, and the soil below is fairly dense with clay. The plan was to till the soil and then add up to a foot of very good new top soil for bedding plants, perennials, etc... What do I do to the roots? My inclination is to go in with a hatchet and remove as many as I can. This area is approximately 24 inches from the base of the hedge - the trunks of the cedars. If I hack at the roots, is this going to kill part of the hedge? Is it best to just replace the black plastic? I'd really appreciate some advice before I take the next step.