Hi, Green Zebra, while not an heirloom in the purest sense of the word because it is only a few years old, is an interesting novelty developed by Tom Wagner of the now defunct 'Tater Mater Seed Company. I have grown it with success. How long have you had it in the soil? There are a myriad of reasons why seed won't germinate. Send me an address and I'll send you some more seed. Chuck Wyatt