I bought this plant from an “unnamed” table at a nursery in Baton Rouge in the spring of 2013. It has survived 16deg f temps. The plant was planted in full sun. Because the leaves looked tropical, I believed the cold weather would kill it. Thanks for your time.
I think that this is cardoon (Cynara cardunculus), also called artichoke thistle, which can be a bit variable, and is grown both as an ornamental and a vegetable. It resembles several species of thistle [Cirsium] but they would unlikely be sold except for native plantings. For a start, go here: http://en.wikipedia.org/wiki/Cardoon but they do not have many pictures of the leaves, so just google ‘cardoon’ to get many more to compare with. Scotch thistle, Onopordum, also looks a little like this, but is very prickly – cardoon is not prickly.
I hope this helps!
Steve Hill, Ph.D. Botanist, SCNPS