Q: Hi Debbie! Love listening to your show!
I have a tree question for you. We have three globe willows, planted in the fall a year apart. I know they are susceptible to bores, so I treat them with tree and shrub systemic every spring. I poured the systemic around them on February 22nd. Three weeks to a month later, I noticed on the youngest tree (2 1/2 years in the ground) there was a foamy substance oozing out of two holes on opposite sides of the tree, approximately four feet off the ground. Well, the other two trees are doing the same thing only further up in the tree. All are oozing from two holes. So, does this mean they have bores and that is the systemic coming out? If so, do I need to treat them in the fall as well as in the spring? The trees look healthy, but we are concerned.
Thanks in advance for your help,
Cathy

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A: Thanks for listening to the radio show and thanks for your question. It sounds like your trees have something called Slime Flux (another name is Bacterial Wetwood). Slime Flux is caused by a bacteria that gets into the tree through a crack, split or pruning wound and causes the sap to ferment. As it ferments, it builds up pressure and finds another crack where the fermented sap can ooze out. Sometimes it’s foamy and it’s usually fairly smelly. Insects seem to like it quite a bit because it’s like their own neighborhood pub.

You might notice it worse in the early spring and fall as the trees are waking up and getting ready for winter. Because of the bacteria, the sap becomes quite alkaline and causes discoloration of the bark and may damage plants or grass that are growing underneath the tree. There is no control for this disorder and trees can live with this disease with no real problem.

They used to believe that drilling a hole to drain the sap away from the trunk and relieve pressure was the way to go, but realized it was just causing more injury to the tree. Since this doesn’t really harm the tree, it was decided to just leave the trees with this problem alone.

This seems to be a disorder more prevalent on fast growing trees, such as the willow, Siberian Elm, and some of the fast growing maples. It can also affect other species, but seems more common on the fast growers.

I hope this helps!

Happy Gardening,
Debbie

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