I planted what is commonly called a contorted filbert or "Harry Lauder's Walking Stick" last year. The tree arrived by mail from a nursery in Illinois, around 2 feet high and contorted. I planted it in my yard in Western North Carolina where it didn't grow. This year the plant has come back and is growing very well, however, it's not contorted! The leaves look like filbert leaves, but the stems are straight. Is this tree a grafted tree and is it possible the original took over and killed the graft?
Yes, root sprouts from the rootstock, below where it was grafted. A very common problem. Note that "Harry Lauder's Walking Stick" is a cultivar of Hazel (Corylus avellana) not of Filbert (Corylus maxima). The rootstock sprouts will also be Hazel.