Plum Tree Problems in Minnesota

Cold Damage

• The most restrictive problem facing plum trees in Minnesota is the harsh winter climate. Because plum trees bloom early in the spring, the flowers and blooms of the tree are frequently injured by frost damage. As a result, only European or hybrid plums grow acceptably or well in all areas of the state. The European plum (Prunus domestica) pollinates itself while hybrid plums (P. salicina x P. Americana) require another hybrid plum tree nearby for pollination.

Bird Feeding

• A significant pest of plum trees in Minnesota are birds. The damage they produce by nibbling holes or eating the whole fruit can drastically reduce the yield of trees that are planted as a food source. This problem can be minimized by netting the plum tree in areas where protection is desired. When the fruit is nearing ripeness and ready for harvest, some protection from birds can be attained by hanging aluminum pie pans from the branches of the tree. which is only a short-term solution.

Other Problems

• The plum curculio is another pest that presents plum tree problems in Minnesota. A beetle, the adults overwinter and attack the fruit of the tree as it begins to form, chewing holes through the skin and feeding on the pulp. Eggs are also laid, with larvae-infested fruits dropping to the ground in June. Insecticides are effective in controlling infestation by this pest. The diseases brown rot, black knot and oak root rot also pose significant danger to the health of the plum tree in Minnesota.

Minnesota Zone Map

• The University of Minnesota Extension Service has developed a state hardiness zone map that details the areas of the state in which specific European plum cultivars and hybrid varieties can be planted and harvested with success. For example, the Mount Royal European plum may be successfully grown in the southern half of the state but will experience problems in vitality in the colder, northern regions of Minnesota. This state map is distinctly different from the U.S. Department of Agriculture Hardiness Zone map.