As I mentioned previously, big garden centers leave a lot to be
desired when it comes to their selection of local flora. This
doesn't mean that they're useless, though. For instance, here in
Wisconsin, one of the prettiest and most versatile native trees for
the garden is the Northern White-cedar (Thuja occidentalis), more
commonly known in the garden trade as Arborvitae - and you can find
it literally anywhere that sells landscaping plants. Make sure you
know what you're buying, though - to use the previous example, the
northern white-cedar isn't the only plant sold under the name
"Arborvitae". Still, if the garden center has a plant you like,
don't be afraid to do a little research - you might just find out
it's native to your area!

Smaller, locally-owned nurseries are a better place to look than
the big garden centers - sometimes they even specialize in native
plants!  Plus, you're contributing to the local economy when you
buy from them, so why wouldn't you want to shop there?