They will be from below the graft. Prune them off carefully, and keep an eye out for more new sprouts from below the graft.

Resin

Prune anything like that out.

Dax

Hold it! Weeping cherry trees sometimes throw up new upright branches from above the graft that are those of the scion grafted on top and not rootstock or interstock suckers. These should be left in place to enable the tree to enlarge itself and produce a layered crown that is more interesting and elegant than a squat mushroom shape.

Any such stems soon arch over to assume the expected pendent habit. These also have the same leaves and flowers as the rest of the weeping top. Rootstock suckers will remain upright and have the often thicker twigs, bigger, broader leaves and different flowers of the rootstock - which is still tending to be sweet cherry (Prunus avium) on most sprouting specimens seen here. Dwarfing rootstock 'Colt' and perhaps others has also been employed, and will have its own, different characteristics (I obtained a rooted 'Colt' cutting from a fruit tree nursery and grew it for a short time to see what it looked like. It had pendent pink flowers that smelled of melons or something similar).

thanks for the replies.these branches have been growing since last year.i thought they would grow out and drop,but they haven't.i'm glad it's safe to cut them.