Since they're "borderline hardy", i'd not cut them back at all this fall or winter. Wait until the core of winter's cold is behind you, such as in early March.

Keeping the dry stem on a marginally hardy herbaceous plant can help protect the root crown, et. al. from ackward freeze/thaw issues and introduction of rot into pruned/dead stems.

Thanks for the info. Would you recommend additional mulch around the base? Also I use pine straw a lot. Would the acidity be an issue?

Don't cut back anything that has a pithy stem, as freezing rain, ice and snow can go down and damage, as Gusolie has already indicated. I use heavy mulches of whatever I can find, usually shredded leaves or pine bark mulch. I don't buy much pine straw as it seems too formal for my areas. And, I really pile it on...got brugmansias and Lantana to come back this way. I am in a cold zone 7.

Appreciate the way you folks are letting me put off some yard work till later.
When I passed on your advice to a neighbor, he wondered about some first year dwarf ruellia (sp?) he has that is supposed to be for zone 8 and above. It is a spiky ground hugging plant about 8-10" tall and some still flowering. Would you recommend also just letting it be still spring or cover it with a lot of mulch.
Thanks again