Saint Croix is a wine grape variety developed in 1981 by American grape breeder Elmer Swenson of Osceola, Wisconsin.
[1][2] It goes by the synonyms Saint Croy, E.S.
2-3-21, and Elmer Swenson 242.
[3] It is a cross of V. labrusca x V. riparia grapes with cultivar crosses [E.S.
283 (Minn. 78 x Seibel 1000) x E.S.