Is there anywhere you could sink them into the ground for the winter? I overwintered about 50 gallon-size pots of winter sown perennials by digging a trench wide enough to set them in, two abreast, then filling the dirt back in. I didn't lose but a handful. Another suggestion would be to line them up against your south foundation if possible and mulch them with pine boughs or straw. I use my east foundation for convenience but the idea is that some heat escapes through the foundation and marginally warms the soil closest to it. There's someone on GW who grows cannas in Z5 that come up reliably every year because they're growing close to his south foundation. I know heat escapes along my south foundation--that's where the snow melts quickest.

I DO have an unheated garage and I stack dormant plants in pots one on top of the other in large, deep storage bins inside. I think even that much protection bumps them up a zone winter wise. I sure hope it works with the 'Fan Scarlet' cardinal flower I hope to bring through the winter this year. My cellar is too warm because I heat with a woodstove that keeps it above 80 degrees most of the winter.

Bags of leaves might work but I can't say for sure since I've never tried it. The pine boughs/straw worked for me the past 4-5 seasons. If possible, wherever you decide to line them up, a north-facing wall is likely not the best choice.

Size matters--if you have any large planters that you'd normally bring through the winter, set some of those smaller pots in those.

Thank you, gardenweed!
My ghetto resides on a west facing wall that gets full sun, and there is a dryer vent there which should add some warmth.
I don't have any space to dig the pots into the ground.
I think I will just push them up against the foundation and surround them with bagged leaves.
Teresa

You could also push them up against the foundation and then place a row of concrete blocks as a border to hold in the bagged leaves. The concrete blocks should act as a heat sink and help minimize temperature fluctuations.

Claire

Thank you, Claire!