Stir serve and serve up.
Ok, it's easy to get red maraschino cherries, and I remember seeing green around Xmas (at least in my childhood) but I nor anyone at the bar can remember ever seeing a white one.
Apparently this drink is a true hazard to keeping a 'consistent maidenhood' so ladies beware!
The Gentleman's Companion, vol. 2 by Charles H. Baker, Jr (1939)