Manihot grahamii / Hardy Tapioca / Graham's Cassava: a native of Eastern South America, from Brazil through to Argentina. I've done a quick web search and this has been successfully grown as far north as North Carolina. (This photo said it was taken in the Pacific NW).
Zantedeschia aethiopica 'Crowborough' arum lily - Unusual, pure white hood-shaped flowers that are up to 10-15cm (4-6in) long are produced from late spring to mid-summer. It makes a striking architectural clump with lovely arrow-shaped, glossy dark green leaves. It looks great grown beside water as a marginal plant and can be left outside in most frost-prone areas if it is given a deep winter mulch.