This was a surprise. Returning home from Paxon Hill Farm nursery, I took Covered Bridge Road, a small, little known byway. As I rounded a curve, I saw this colony of Digitalis ambigua growing in the grass on a bank. It looked so natural I thought it might be native, but I don't think any digitalis is native to North America. I've looked on the Internet, but haven't been able to find the origin of this plant. Is there a good, comprehensive reference for origins of plants we grow as perennials?