My grapefruit and lemon tree were both planted in ground at the same time. It's a Meyer lemon tree and it took off, but the cocktail grapefruit is as small or smaller than when I bought it. I have tried various things to improve the soil etc. now, I would just like to graft the grapefruit onto the lemon tree. Does anyone know if this would work. By the way the grapefruit variety is called "cocktail" and is supposed to be a specific variety also called "vodka." This "cocktail" name not to be confused with trees that have various varieties grafted on one tree.