UACES Facebook Wet Wood/Slime Flux

Wet Wood/Slime Flux

(October 2008)

QuestionI have a sugar maple, ‘Autumn Blaze’ about five years old in my front yard facing the south. It is at least 10 to 15 feet tall.  I recently noticed an area close to the bottom of the tree about 7 or 8 inches from the ground that is bleeding a black substance.  Is this usual or should I be concerned?


AnswerOne of two things can be happening.  Maples are notorious for “bleeding” sap from any wound.  If something wounded the tree such as a weed eater or lawn mower, this could simply be the case and is nothing to worry about.  The other scenario could be wetwood or slime flux, which is caused by a bacteria.   Gasses and liquid by-products of the bacteria cause the internal pressure of the sap to increase, forcing the liquid to ooze out any opening along the tree. It tends to have a sour or fermented smell to it and is quite attractive to insects. It can be dark in color or white and foamy.  While it doesn’t signal imminent death, it does tell you the tree is stressed.  Keep the tree as healthy as possible with regular watering.  Try to use your garden hose to remove the sap from the trunk of the tree as the fermented sap can be damaging to the trunk of your tree if left there.  This problem is usually more common during spring and summer.

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