First, I want to make very clear that Chicagoland is not in a drought this year. I repeat, there is no drought. I also want to emphasize that I mulched the garden. The good covering of mulch is what delayed my discovery of the problem. My first clue that something was amiss was when a previous healthy Columbine started wilting. When I moved the mulch, I found a bunch of big, deep cracks in the soil. To try to determine how deep the cracks went, I stuck my Japanese type weeder, affectionately known as my "Hari Kari" kife, into the crack.
It's 6 1/2 inches from the tip of the blade to the hilt. I'm shocked that the three Campanula 'Dickson's Gold' haven't started dying.
I don't know why my soil does this, but every year it develops these big cracks. I just keep filling them with compost and hoping for the best. Guess I'd better start watering the garden again.