My vote would have to go to Nutmeg Elf. It has survived here, with no special care, for years and years. A couple years back, I moved a clump of it from out on the hill to the "good" bed along my front sidewalk. Wow, did it take off. Had over 50 scapes this year. I know that it is unlikely to win, because the small flowers would be considered out of proportion to the scape height - but I, personally, love small flowers on tall scapes.
I have grown many of the cultivars on the list this year, but NUTMEG ELF out performs them all.
