I recently bought a young weeping cherry tree, most likely grafted near the top (~3.5 ft). There are two branches growing out of the trunk that don't match those of the weeping branches. I don't know what tree the trunk is, but are those branches from the type of tree that they're growing from?
Anything growing from below the graft line is the graft stock growth. These should be pruned from the tree as soon as they appear to keep from root stock take over.