OP here and thank you both very much for your thoughts. Love these ideas and will give them a try.

Agree with PP, plus how deep are the containers? I assume for privacy you want tall plants, which generally need deep roots.

But you also can try heuchera if there isn't too much sun, and you may manage to get ice hardy pansies to make it a long time.

I like your option of short variety of native grasses, which will have dried winter interest and may re-emerge in spring if the roots can have enough room. See if pansies will survive among them for color.

Generally, it will be a challenge, but try choosing drought tolerant perennials that are hardy two zones north of you, like dianthus, yarrow, Christmas fern, nepeta, Woods blue aster -- not sure those get you privacy though.

Perennials are hard to grow in containers. Containers will get a LOT more freeze-thaw cycles in the winter, so if you do have a perennial or a shrub in a container you likely need to have it under cover over the winter. The other thing is that containers require more fertilizer, because they need a lot of watering and drainage so more washes out.

You can grow Hollies and other things in very large containers, but that doesn’t sound like what you have. Are yours on the deck floor or hanging on the railing?

If the railing, you could get some little evergreens for winter. But I would treat them like annuals and start over in spring.

A lot will also depend on which direction they are facing. Can you set up a drip watering system? Or are you going to have to carry water to them by hand?

Hello, I recently bought railing planters for my deck. I know I am out of season, but wonder if there are any perennials I can plant now that will survive the winter.

My goal is privacy and I am experimenting with native Sea oats and switch grass right now.

Thanks for any ideas or suggestions, even if it’s to tell me this is mission impossible!