Weeping cherry trees are the ones you see in Washington D.C., the focus of the annual Cherry Blossom Festival. Planting the trees so they can get proper air circulation, pruning and keeping the area free from debris will go a long way in helping to prevent serious diseases that can affect the weeping cherry.
The weeping cherry tree can grow to a height of 20 to 30 feet and a spread of 15 to 20 feet. The tree produces light pink flowers of about 1 inch in diameter and black fruit that is less than ½ inch in diameter. The leaves are glossy green in the summer and turn bright yellow in the fall.
The weeping cherry tree likes a moderate climate. It does best in hardiness zones 5 to 8, from southern New York and New England to the northern border of Florida and most of the middle of the country. As a point of reference, Washington D.C. is in zone 7.
Signs of Disease
The weeping cherry is susceptible to several diseases. Black knot usually appears on the newest growth as small swellings that are light brown and break open as they grow larger. Silver leaf is a fungal disease that gives the leaves a silvery coat. In some cases, the silver will not appear and twigs and branches will just die back. Powdery mildew appears as white spots on leaves and twigs. Cherry leaf spot appears as small, dark spots with white spots in the middle on the leaves. Brown rot is a fungal disease that appears as powdery tufts of brown/gray spores on the fruit, blossoms and small branches. Bacterial canker appears as dark brown spots on leaves and cankers on trunks, limbs and branches that ooze a gummy substance.
Small twigs infected with black rot will die within a year. Larger branches can last for years, but they too will eventually succumb to the disease and the whole tree can die. Silver leaf can defoliate a tree and in the worst cases, the tree will die. Powdery mildew can make the leaves curl up, die and drop off. With cherry leaf spot, the leaves can drop off. The fungus lives in these leaves over the winter, gets splashed by rain and falls on the new leaves in the spring. With brown rot, the fruit rots, shrivels and becomes covered in a brownish/gray substance. Spores then spread to the twigs and other parts of the tree. Bacterial canker causes the leaves to wilt and die.
In all instances, the diseased parts must be pruned off and disposed of. Trees infected with black knot should be sprayed with a fungicide for ornamental trees in the spring and fertilized. No chemical controls silver leaf. Powdery mildew and cherry leaf spot can be controlled with a fungicide. Trees infected with brown spot should only be sprayed with fungicides three weeks before the fruit ripens. With bacterial canker, spray with a copper sulfate fungicide in the fall.