Ulster Prince Potatoes This page first published: Apr 6, 2005 · Updated: May 12, 2018 · by CooksInfo. Copyright © 2020 · This post may contain affiliate links · This blog generates income via ads · Ulster Prince Potatoes are oval, with buff skin and white flesh. These are waxy potatoes. Early harvest. History Notes Ulster Prince Potatoes were developed in 1947 by a John Clarke from Mosside, Ballymoney, County Antrim, Northern Ireland.