Red Star plums are huge fruit with red skin and incredibly juicy, sweet yellow flesh. Red Star trees stay dwarf (10 ft) and have acclimatized to our -40 C winters(zone 2-3). Our 30 yr old mother tree of Red Star has never shown any black knot disease...so we conclude that it is black knot resistant. Produces fruit without a pollinator plum near by but to get a full crop you may require a compatible pollinator plum like Gold Star or Arctic Hardy.