I need some large evergreen shrubs. I've been looking through all my suppliers listings and I can't seem to find the right one to fill the space. I am looking for some suggestions on a 20' x 20' evergreen shrubs, that can hold a fairly spherical shape naturally with little to no pruning. Originally I was thinking about putting in Mugo Pines, and letting them fill naturally, but I'm not sure if they are hardy enough for the space, and we have problem with scale on mature mugos. Full sun, crappy fill soil from newer construction. Thanks.