A seedling selection of Mount Royal, Northern Blue is one of the hardiest European plums out there. We’ve seen one of its parents, Mount Royal, thriving in harsh locations east of the divide, including Columbus, MT, where it has withstood temperatures as low as -42°F. Based on this, we believe Mount Royal is hardy to at least -45°F.

Flavor Profile

Its flavor is smooth, offering a great combination of sweetness with a slight tartness in the skin. Northern Blue ripens here in Missoula in early September.

Rootstock and Cold Hardiness

These trees are available in several sizes and are grafted onto Krymsk 86 rootstock, which is hardy to -45°F.