I would give them winter protection. Other than moving to an unheated basement you can wrap them up in blankets or burlap.

I have had mixed results with leaving plants out unprotected in the winter. My Heritage Raspberries have thrived with no winter protection but blueberries and others have died. I learned the hard way that they need to be protected.

It's better to be safe than sorry.

Thank you for your help!

No problem. If you google Winter Protect for Containers you will find lots of further information.

What kind of shrubs and trees do you have in containers?

I would also add some bubble-wrap, thats also an inexpensive method to wrapping.

Most of my container plants are roses that are hardy to zones 4,5 and 6. The trees are small Japanese maples,some magnolia stellata,and a couple of small corkscrew hazels. I have kept some of the Japanese maples (beni kawa) and the corkscrew hazels out for winter interest,moving them to more protected areas when it got really cold,and they have been fine. The other Japanese maples were over-wintered in the unfinished basement with the other plants. I really don't have a big enough protected area outside for all of my little trees,so putting most of them in the basement was the best option. My other container plants are Miss Kim lilacs and some crimson and gold quinces.

christine1950 mentioned bubble wrap - I second that. I am also getting supplies around for this years winter protection. I have thick blankets from thrift stores and bubble wrap so far. The key is layering. A layer of bubble wrap, blankets, burlap and even insolation will help.

If you like the winter interest then make sure you keep an eye on the temperatures. When it drops below 32 degrees make sure they are layers with materials or moved inside a unheated room.
If they must stay outside grouping them together next to a building or wall will help a little more.

Best of luck with your plants. Hope these tips help.

Whether or not you need winter protection will depend on the hardiness of the plants and the size of the container. Some plants will be much more sensitive to cold than others.....and these are the roots we are taking about, not top growth. Top growth is very much prone to winter dieback in all sorts of situations, inground or in containers - but it will typically come back with warmer spring weather and the resumption of the growing season. It's the roots you really need to be concerned about. And the larger the container the more soil to act as an insulator to the roots, just as in the ground.

In zone 7, your need to winter-protect will be much less than in colder zones. Your inground soil seldom freezes solid any deeper than a couple of inches. Depending on container size (bigger is better), you can expect similar results. 32F is not a temperature you need to worry about. Soil doesn't freeze at that temperature - that is just a frost indicator. It's when the temps dip into the low 20's and stay there for an extended time that you need to be concerned.

Regardless, I would not take the plants indoors. An unheated garage is fine. And bubble wrap is an ideal insulator, by far the best of the alternatives listed above.

FWIW, I garden entirely in containers and granted, I am in a slightly warmer zone but I have never bothered to winter protect any of my containers except those that held non-hardy plants. Have yet to lose a single plant to cold damage :-))

Thank all of you very much for your advice!