Disease-Resistant Ornamental Plum Trees

Ornamental plum trees are prized for their showy flowers and purple leaves.

Ornamental plum trees, sometimes called flowering plums, are part of the Prunus family of trees, which also includes cherry and almond trees. There are many species of ornamental plums that produce showy flowers in the spring and dwarf, inedible fruits in the summer. To find the hardiest varieties, ask a gardening specialist for the type of ornamental plum tree that is cultivated for your specific growing zone and climate.

Common Plum Tree Diseases

Diseases common to ornamental plum trees are rust mites, black knot, brown rot and plum pox -- a viral disease. Rust mites are tiny insects that attack leaves, causing them to curl and turn a silvery color. Black knot is a fungal disease named for the black growths or knots that form on branches. Brown rot is another fungal disease that attacks fruits, flowers and new growth, leaving a visible brown and fluffy mildew. Plum pox is a virus that is spread by insects such as aphids, causing yellow or brown spots, or rings on fruit.

Myrobalan Plum

Myrobalan ornamental plum trees (Prunus cerasifera) are very hardy in U.S. Department of Agriculture plant hardiness zones 5 to 8, and they are resistant to most diseases. This flowering plum tree produces white or pink flowers; some varieties have purple leaves. The "Thundercloud" variety grows up to 18 feet tall and maintains a rich color during the growing season. The "Krauter Vesuvius" variety is very tolerant of cold and drought.

Japanese Varieties

Many gardening experts say that Japanese varieties of ornamental plums, including Prunus salicina and cerasifera, are more resistant to diseases than American varieties, especially to black knot. Most of the Myrobalan plum trees are of Japanese origin, as well as trees with the common names Japenese apricot or Chinese plum (Prunus mume). Bungo varieties of Japanese ornamental plums, named for the Bungo province of Japan, are resistant to black knot.

European Plums

European plums (Prunus domestica and insititia) are slightly larger than their Japanese ornamental counterparts, but they offer good disease resistance and hardiness in colder zones. The Stanley prune plum has good disease resistance, though the fruits are slightly larger than most ornamental plum varieties. Other varieties of European plums include Bullace, Damson, St. Julien and Mirabelle.

References

• "Complete Trees, Shrubs & Hedges"; Jacqueline Hériteau; 2005
• "Hardy Ornamental Flowering Trees and Shrubs"; A. D. Webster; 2004