Falconman,
I live near St Louis but I have a farm and hunt near Linn, MO I drive right by your place whenever I go between. If I had a good way to bring our tractor over there, I'd help you with those stumps but I have a recommendation that Might be just as good. My first question is, How are you working up the ground. it looks like you are just raking with the throw and go but with the perennial mix, are you plowing with a pull behind? If not, and you are working the ground by hand, just go around the stumps and cut them as close to the ground as you can. Then drill holes in the top with the largest drill bit you have or hit the top with an axe several times to cut the top They'll be fertilizer in a couple of years and your perrenial plants should still be growing. As Far as North vs. South, I've found that we can plant either way in our region and they'll still do well. Just don't try to start new plants in the middle of the summer. You could probably plant until the middle of June since we've got some decent rain and have some more coming but then I'd hold off until it starts to rain again in Sept-Oct. As far as fertilizer, You should probably put some with it when you plant and then I'd wait for any more until fall also. You can over-fertilze in the summer and burn the plants. 10-10-10 or 12-12-12 is fine, The MFA in your area sells fertilzer in bulk too but the last time I checked, last fall, it was more expensive than Lowe's, Go Figure. Good luck with what you're doing. I was almost thirty before I got into doing the type of thing you are starting. Bravo!!