Well, among the natives there is scruffy pea (and I think it's cute), but I dunno if it's a bulb...but it's certainly perennial.

Runner beans, Phaseolus coccineus, produce thick fleshy tuber-like roots but they would probably not over winter in your zone.

I wish this double posting thing would stop!

This post was edited by floral_uk on Tue, Nov 5, 13 at 12:12