Suckers are growth that arises from the base of the tree or from roots. Watersprouts are the growth that appears on major branches and grows straight up. The included photo was taken during the dormant season to more easily identify the watersprouts. This may have to be done several times during the summer. It is important that these are removed during the growing season as removing them next spring will just encourage more watersprouts and suckers to appear. (Ward Upham)