Of all of my accomplishments as a gardener, this is one of which I am most proud. And it took a lot of patience to get even this far: I collected the seed in either 1991 at Virginia Beach or in 1994 at Zuni, Virginia; Wayne and I used to take occasional birding trips to those areas back then. Smilax are very slow from seed: not only does the seed sometimes take years to germinate, but once germinated the resulting seedlings can be very slow growing. The plant in the photos above took years before it began to put on any size at all, but now it annually produces multiple ten to fifteen foot canes.
So far it has not ever shown winter damage, and it now blooms annually. In fact, it set seed last year and the resulting seeds survived the winter. I collected some of these early this year, and one has already germinated and put up a sprout.