I believe St. Paul is zone 4, unless you have some warmer influence, like from the city itself. Miscanthus sinensis 'Strictus' (Porcupine Grass) is reliably hardy to zone 5.

If you didn't have good snow cover during the coldest part of winter, you should have provided some protection for the plants, especially in their first winter.

Keep an eye on them, and keep your fingers crossed. It may just be the soil isn't warm enough for their liking yet.

Thanks Donn, I'm concerned 'cause everything else is coming up fine.We did have a lot of late snow. I figure by the end of June should be enough time to wait.