Could you provide a source to explore this a little further? I haven't heard that before. I know there are differences among plants; some hostas are clearly day-length-sensitive (though not native; most Asian). On the sheltered east side of the house, the Ozark or spring witch hazel (Hamamelis vernalis) bloomed strongly right along with the earliest hellebores during the freaky warmth of December; maybe that doesn't count as a counterexample since it's not actually native here in western Virginia, though.

I almost mentioned that, Kathy. Like many plants such as heathers, those set out early in the spring survive much better since they are able to establish root systems. One problem we have here is the freeze thaw cycle, but that may be because we are 30 miles from the ocean. I have been able to keep them for 5 years or so, but they only bloom early (Jan-Feb) during mild winters.

Growing it in the garden. Stock came from a pink selection from Maria at Mont Echo years ago. The one flat she left with us has spread into a large colony under the white pines. I imagine that our native plants are blooming on the ledge in the woods though, I've seen them bloom in January thaws in the past.