That is the question--sorry, Hamlet. And White Flower Farm has some help with the answer: an article on Plants Slow to Break Dormancy. They have a lot of other articles in the Newsletter section of their Garden Help.
If you want to learn more about the plants native to your area, a good place to start would be The New England Wild Flower Society Guide to Growing and Propagating Wildflowers of the United States and Canada by William Cullina. He has done a good job creating a general reference work that can help [...]