Heartnut cultivars yield a larger easier cracking nut. Heartnut seedlings are listed throughout the trade as hardy in Zone 4. My experimenting has shown the same. Grafted cultivars are listed by pretty much every nursery as Zone 5. I am trying them all here in Central VT, I think they will be ok in protected micro-climates, but only time will tell. HEARTNUT TREES CAN NOT BE SHIPPED TO MO, KS, IN, MI, IA, NE, MN
Gordon- selected by John Gordon, supposedly a seedling of Stealth. Long pointed nuts , longer and pointier then Stealth.
Hershey Farmhouse- a large grafted plant at John Hershey's farmhouse in Downingtown PA, most likely "King" a selection of John Hershey. Medium sized nuts, productive.