The Heavenly Blue's (Ipomoea tricolor) don't reseed here, or at least very rarely. And I've never had an I. nil reseed. But the Ipomoea purpureas most definitely do. Oh, and Don, Swallowtail Seeds is an excellent vendor. I still have some seeds from my Yoi no Tsukis, but I don't know if they're still good. Another one that I really like (but it's an I. purpurea and I get volunteers every year) is Jamie Lynn. The photos don't do it justice; the flowers have an opalescent look to them that's hard to capture.
Morning Glory (Ipomoea purpurea 'Jamie Lynn')
