The purple leaf plum tree (Prunus Cerasifera) is a deciduous ornamental tree also known as the cherry plum or thundercloud purple leaf plum. It is mainly grown for gardening and landscaping because of its intensely purple or reddish leaves and pink flowers. It is a relatively small tree with a short life span. It grows about 25 feet and only lives about 20 years. It starts in early spring with fragrant flowering. The leaves emerge quickly after the flowers fade. Small fruit begins to appear in July and do not ripen until August. The leaves start to fall off in August, and by the end of September the tree is bare. The purple plum is susceptible to several diseases.
Black knot is the most serious disease of ornamental trees. Hard black long knots form on the smaller branches of the tree, often killing them. If left untreated, growth will be stunted, and the entire tree will eventually die. Immediate pruning of diseased areas can help stop the spread.
Verticillium wilt is caused by the fungi Verticuillium albo-atrum and V. dahliea. It is a vascular disease meaning it pertains to the tissues that circulate fluid. Symptoms of the disease include leaf wilt, die back of branches, and in more severe cases the whole side of a tree can be infected. Other symptoms can include smaller, browning, or scorching of the leaves, poor growth and stunting. These symptoms can occur over years, with years of "remission" in between, or they can advance quickly until the tree dies. The best control is to keep trees as healthy as possible. This includes proper planting, watering and fertilizing. Pruning helps remove infected areas but will not eliminate the disease as it spreads up from the roots.
Cankers can be the result of wounds or diseases on bark, branches or the main trunk. The cankers are injuries or dead sections. Cankers result from disease, especially fungi or bacteria that can't infiltrate the bark directly but can collect at wounded tissue. The disease can cause severe damage if it kills all the bark in one spot, girdling, or cutting a rut in the trunk and stopping the flow of sap between the roots and the branch or stem. Cankers caused by lawn mowers or other equipment can't kill the tree but create places for invasion of diseases. Again, the best control is to keep trees health in the first place. Water regularly, mulch around the trunk so as to avoid injuries, fertilize properly and prune in the early spring.
Bacterial spot is a serious disease that severely attacks trees at the leaves, fruit and twigs. Infection looks like small purple or black spots on the surface of the fruit and eventually underneath the spots become soft. The spots on the leaves are angular. At first the spots look like water spots, but eventually the spot leads to a shredded appearance of the leaf before they turn yellow and fall off. Control methods include monitoring the fruit and leaves for any symptoms. Chemical sprays may help reduce the level of infection. To work properly they should be applied before symptoms occur, just before growth starts again in the spring.