07/27/2026
Ever notice dark staining or wet-looking spots on the bark of a tree?
On some trees, especially elms, that can be bacterial flux — sometimes called slime flux or bacterial ooze.
It’s usually connected to a wound or stress point in the tree.
A lot of times, it’s not something people notice right away. It just looks like the bark is stained or discolored.
But like most things with trees, there’s usually a reason it’s happening.
If you’re seeing something like this, it’s worth taking a closer look — especially if the tree has other signs of stress.
