Problems With a Weeping Mulberry Tree
The weeping mulberry tree (Morus alba) produces suckers and is invasive. The weeping version is fruitless and is often used for landscaping purposes. The weeping mulberry grows up to 60 feet in height. The crown grows as wide as 60 feet, though the males are smaller-only growing up to 40 feet in height with a 40-foot wide crown. The weeping mulberry grows in any type of soil, as long as the soil is well drained.
The weeping mulberry is sometimes plagued by bacterial blight, which is caused by Pseudomonas syringae pv. Syringae. It is also known as blossom blight or shoot blight. The blight causes brown spots on the leaves of the weeping mulberry. As the spots get bigger, they cause the leaf tissue to become malformed. Malformed leaves fall off the tree early. If the disease is advanced, as it spreads to other branches on the tree, the leaves turn black and wilt. Keep the tree healthy by providing enough water and making sure it has the proper nutrients. Water from the ground—do not wet the leaves. Thin trees that are too close together. One way to get rid of bacterial bight is to remove all infected branches and discard them (do not put them in your compost pile). Pesticides can be used only if the disease gets out of hand and becomes severe.
Several fungi cause powdery mildew. The disease leaves a dusty, white or gray coating on the surface of the leaves. It starts out as round, white spots. Powdery mildew causes stunted leaf growth, distorted buds and branch tips, and premature leaf drop. Powdery mildew is treated with fungicides. Check with your nursery to obtain the proper chemical for the specific cultivar of weeping mulberry. Remove all leaves and other plant matter than might have fallen from the tree. Discard in the trash-do not compost infected material, as you could spread the disease.
The term "witch’s broom" comes from the German word "hexenbesen," which means to bewitch. A weeping mulberry affected with witch's broom might have one or more bundles of dried twigs with no foliage on them. Several types of biological and environmental stresses could cause witches broom on the weeping mulberry, including fungi, phytoplasmas, mites and aphids. Testing to find the cause of witch’s broom could be costly if no other symptoms arise. Prune the affected branch and discard it in the trash. If you know what caused the condition, treat for the cause.