Both should be winter hardy in OK. A. incarnata is hardy to zone 3 and A. tuberosa is hardy to zone 4. Milkweed generally is very late to emerge from the ground compared to many other plants and I often don't see any sign of life from various milkweeds until April down here in southern OK. They usually do die back to the ground in autumn or winter and are very slow to show signs of life in Spring.

Thank you for the information. Just what I needed..........Maryl

You're welcome.

I am in Texas and the milkweed start sprouting around April.

Thanks Gretchen. Where in Texas are you?......Maryl