Hopniss, or groundnut (Apios americana), is one of two major native North American root crops (the other is Jerusalem artichoke). Although it is somewhat slow growing in the Pacific Northwest, it is a truly perennial crop that will produce good yields if allowed to grow for two or three years. The tubers are much like a very firm and dry potato and they can be used as a substitute in most potato recipes. It is a strong and attractive climber that grows really well along a fence or wall.