Elderberry, or sambucal, is well known for it's anti-viral properties. It also grows quickly and provides a beautiful centerpiece, or even screening element, to the garden. The flowers are showy and plate size in the spring, giving way to dark berries that last into the fall.
I do endorse Nature's Way Sambucol Black Elderberry Extract Syrup, as a teacher and a mom we use it every year. And it is gluten free!