I've caught lots of fish on frogs and I can't remember a single one that I ever caught out of lily pads, just not many around here. Mainly matted milfoil, water willow, and flooded timber or shoreline weeds.

Dean Rojas throws frogs everywhere not just in lily pads but under laydowns and in open water pretty much anywhere. I notice you have better hooks up fishing a frog in open water.

And yes there are lily pads in the midwest.

I havent had the best of luck with hook sets have gotten a few though. But ive gotten strikes on my SK frog popping it over anytype of cover or punching it through the cover not just lillys. Almost every pond/lake ive fished in nj/ny has lillys