Can someone help me identify this plant i have no idea what it is but its growin in my back yard?

The plant you showed is not marijuana although it looks similar. MJ has serrated (tooth-edged) plamate (finger like leaflets coming from a central point), the same as the plant you showed. BUT- MJ leaves come to a sharp point at the tips and the serrations are different than in your picture. What you have looks like some kind of ornamental but I am not sure what it's called.