Also, will the new surface after the mulch is laid down be higher than the current level of the yard? I know you’re supposed to dig low 3 inches below the level of any concrete (driveway or sidewalk), but beyond that, it sounds likes the levels will be 3-4 inches above the current lawn.

Thanks for your excellent question. Yes, you can plant a ground cover that spreads and roots in an area that’s been sheet mulched. For the initial planting, cut a small hole through the underlying newspaper or cardboard so that the roots are in soil. As the plant grows and sends out runners, they will root in the mulch on top. (Make sure you water sufficiently during the initial establishment period). The sheet mulch gradually breaks down to become soil, so the ground cover can continue to develop deeper roots. As it spreads, the ground cover will also work to shade out new weed seedlings. Plus, pulling weeds is easier after mulching, since the ground is looser when it contains decomposed organic material.