Yeah Alex, my gardening doubles as my spring/summer exercise program....plant, weed, repeat! And I know what you mean about the hard soil. Ours is a mixed bag with nice black soil in places and hard red clay in others. We put in a tree in the front of the house, the guys planting it had a bobcat with a scoop on the front to dig the hole. Luckily there were 3 guys because they ended up scraping down 8" or so then had to bring out pickaxes to break up the clay before the bobcat would even make a dent! And the 2 guys not operating it had to stand on the back along with my husband to stabilize it enough to dig even after breaking some of it up.
Since your soil is super hard how does it drain? Do you slightly raise your peonies when you plant? From your pictures of blooms it's obvious they aren't having a problem with the way they're planted, I just know that I'd create a mini-bog if I tried to dig a hole in the super hard stuff in my front yard and backfilled it with more workable soil, how did you avoid that? Or is your soil free draining even though it's hard?