What Zoia said ... watch out for invasives. Yes, they may be ornamentals but could end up swamping your other plants. Of course, I'm also zone 6b so it may be worse here. For example, I've just been digging up and giving away hundreds and hundreds of grape hyacinths. There are sooo many I've planted and regretted but that's for another thread probably in another forum.
As to your original question, I would say you cannot go wrong with anything from Karol Emmerich. She's in Michigan so the zone may be similar to yours. Maybe look for dormant daylilies?
Some of my favorite dormant daylilies are:
ALPHA AND OMEGA (Emmerich)
PRAY WITHOUT CEASING (Emmerich) - really stunning but quite new and still quite pricey
STARFISH PRIME (Murphy-JP)