Are you sure itts not a sucker ? No not you

but a new cherry tree growing from the roots of the other cherry , it's very common in cherries . So if your cherry is grafted then it's a cherry of the root stock .
David
Living in Anjou , France,
For the many not for the few
http://www.permies.com/t/80/31583/projects/Permie-Pennies-France#330873