I'm in zone 4b and looking for plant suggestions. I want to overwinter plants in containers. I'm tired of filling 20 pots every year with annuals. What plants do you overwinter outside in pots?

Hi Meri, In your zone not sure that a possibility. It will be interesting to see what others in cold zones say.
Of course you could always move the containers to a semi heated space for winter.

I wouldn't do it, the roots will freeze, you could try wrapping the pots with burlap and lots of leaves. Other members will have more suggestions on how to protect the roots, and I just thought, the clay pots would probably crack.
Perennials that I have in pots are, hostas, sedum, hen & chicks, I over winter them on my un-heated screened in porch.

I don't think they will survive the winter as I have not tried perennials in pots. If you have some perennials growing in your garden that you could split up , you could experiment with some to see what would happen. Might help if you have excellent wind protection for the pots plus cover them well with leaves, perhaps a well weighted down tarp over them once it freezes would give some extra protection. Moving them into a garage might help but it would be extra work and take up space.

Instead of doing annuals in a bunch of little pots you could do fewer large pots and do tropicals. You could winter inside in a basement. Look for tropicals that have beautiful foliage like cannas, calla lilies. I garden in pots and garden focused on foliage vs flowers which are fleeting.

I am warmer than you so I do not think what I winter outside in pots would work in your zone.

We had a discussion in Perennials doing this. Check this one maybe there are some in your zone.

The thread "Perennials suitable for growing in containers" in Perennials forum

All of my containers are either metal or foam/plastic with a minimum of 8" and most of them 12 or larger.. I only have one pottery container and it gets hauled into the garage every year. I tore down an old (100+ years) shed and found a treasure trove of enamel wash pans, plates, coffee pots and cooking pots plus several galvanized buckets. One of the larger containers can't be moved because the whole bottom has rusted out. I don't have a clue what it was used for as its about the size of a bushel basket, has fluted sides that curve around all the way to the center bottom and 2 hanging handles.

Doing more research I found that for perennials to survive over wintering in pots the plants need to be 2 zones colder than your zone. So since I'm in zone 4b I need plants rated to zone 2. If I move them into an unheated garage I can get by with zone 3 plants.

I did some further research for zone 2 perennials and found quite a lot! Even more for zone 3 plants. I made a list of both if anyone wants it tree mail me. I'm sure its not complete but its more than I expected to find.

I also discovered that if you overwinter pots in the garage you still need to water them. I learned that the hard way.