The purple-leaf plum tree gets a jump on spring by blooming in late January or early February before the leaves bud. The tree needs to be planted in full sun to bring out the purple in the leaves as shade causes the leaves to turn green, according to the U.S. Forest Service. The tree is highly susceptible to a variety of diseases, including brown rot, wood rot and verticillium wilt as well as pest infestation from the peach tree borer, aphids and plum curculio beetles.
A common problem for the purple leaf plum tree is blossom blight, in which first the flowers, then young leaves, turn brown and wither, according to "Grow Fruit" by Alan Buckingham. The cause is a fungus that is introduced to the fruit by damage caused by insects and birds and is the same fungus that causes brown rot, which attacks the fruit.
Problems of the Leaves, Stems and Branches
The leaf curl plum aphid sucks the sap from the plum tree's new leaves, causing them to curl and distort.
In the case of the peach tree borer, the female moth lays eggs in the summer around the base of the plum tree. When the larvae hatch, they tunnel into the bark, according to "Backyard Fruits & Berries" by Diane E. Bilderback and Dorothy Hinshaw Patent. This weakens mature trees and kills young trees.
Verticillium wilt is a fungus that lives in the soil around the tree as well as any dead plant matter, causing the leaves to turn red, brown and yellow; black streaks to form on leaf stems; and branch die-off on only one side of the tree.
Silver leaf is a fungus disease that causes the purple leaf plum tree's leaves to turn silver with brown at the edges. Other symptoms include branch and stem dieback and the appearance of a purple, white or brown fungus on the bark.
Plum trees can develop brown rot, which is a fungus that turns the fruit brown and may herald the appearance of white fungal spores on the fruit. Plums will either shrivel on the limbs or fall of the tree.
Another problem is that the trees are prone to infestations of the plum curculio beetle, which will cut a small flap in the skin of fruit to lay eggs, according to "1,000 Gardening Questions." Once the larvae are in the fruit, on which it feeds, it is impossible to get rid of them.