Hamamelis vernalis is a species of witch hazel whose native range is restricted to the Ozark Plateau. It will grow quite happily in Pittsburgh, however, and is well worth seeking out. The first warm winter day, from about Christmas on, will bring out these intriguing little flowers all over the bush. They’re not all that much to look at, although they make a beautiful ikebana-style bouquet in a vase. But the scent is sweet and very strong; a few twigs can scent a whole house. When the weather turns cold again, the flowers fold up, ready to show themselves once more on the next warm day. Meanwhile, if you cut a twig and bring it in at any time during the winter, it will unfurl its little flowers and get to work pumping out perfume.