There are some wild ones that grow in the sandhills around here but the only one I've been successful with are the ones they had a few years back at the big-box marked as "Baptisia" and it was bought as a plant.

It's too hot for them in anything south of zone 7. Here's a photo of them growing wild near Milford, New Zealand, which I believe is zone 6. Interesting that in New Zealand they're considered an invasive exotic. I guess the picture bears witness to that.

Here's another photo taken miles away from the first one. If you notice, way back in the upper left, you can see another field of them as a purple mass.

Thanks so much. I guess I won't expect fields of flowers but will try them anyhow.

I've grown the annual ones many times, one is texas bluebonnet and one called pixie. These are not near as pretty as the ones up north.