I have a customer that just moved into a new home. All it has is a small mulch bed in the front that is completely flat and a few bushes. They want to me to design a mulch bed, build it up, so it's looks more mound like and plant some bushes, flowers, etc. as well as install mulch and edge. What do you all recommend to build up the mulch beds/flower beds? Should I use topsoil or something else. And should I prepare the soil with something before I plant anything. If so, what should I prepare the soil with?