Negi is one of the kyo-yasai — traditional Japanese heirloom vegetables dating back to the Edo period in seventeenth century Kyoto. Ippon Negi is technically a scallion, but they are grown similarly to leeks. The hollow leaves grow to 60cm (24") long, and the white shanks can be extended by hilling up soil around them as they grow, as you do leeks, with no bulbing. Try grilling for a tasty side dish.