I have NEVER dug ANYTHING that deep, Alex! Planting this year was super easy because everything went in to raised beds I built over the last 3-4 years. Overall I think I moved around 50 cubic yards of planter's mix into 3 large areas, probably raised the levels 8-10" average with the highest spots around 2' above the original elevation. This summer I ordered 20 cubic yards of mulch, still have around 4 or 5 yards to move. The mulch was mostly deteriorated in the main beds and I hadn't put any other than a layer of pine straw down on the newest. It's a big deal here in the spring because peonies will sprout earlier without it, causing more damage than necessary when we get the crazy cold and snow in April. The smaller the growth is when that happens the better chance it'll have to make it through....