for our workflow we typically want to show the entire site as grass, then we use a Subdivive (previous Subregion) to add in our mulch beds and driveways and maybe walk pavers if needed. it would not work for us to not have that main material as grass. if you have another solution then i would like to hear that. Ive tried the suggestion from "rdh3t" and that although not perfect does provide the best results that i have seen at this point.