Slime flux, also known as bacterial wetwood, is a common bacterial disease that affects many tree species, including Siberian elms, maples, poplars, and birches. This condition is often identified by the presence of brown or black fluid seeping from the bark, which can cause concern for homeowners who notice their trees “leaking.” While this may seem alarming, understanding the symptoms, causes, and preventive measures can help manage the issue effectively.
The most noticeable symptom of slime flux is the oozing of dark, foul-smelling fluid from cracks or wounds in the tree’s bark. This fluid, which is initially clear but turns brown or black when exposed to air, often stains the bark and can create streaks down the trunk. The fluid may also kill grass or other vegetation near the base of the tree, leaving behind dead patches.
In addition to the oozing, trees affected by slime flux might show signs of stress, such as wilting, leaf yellowing, and dieback, although these symptoms can sometimes be mistaken for other conditions like Dutch elm. Slime flux is caused by anaerobic bacteria that thrive in low-oxygen environments within the tree. These bacteria typically enter the tree through wounds in the bark, which can be caused by improper pruning, boring insects, poor branch angles, treehouses, lawn mower damage, or storm-related injuries.
Once inside, the bacteria multiply and produce gases and liquid byproducts that build up pressure within the tree. This pressure forces .