Oak tree, 5ft crack, sap oozing at 3ft mark (see images)

Asked July 11, 2018, 2:13 PM EDT

I have two 19 year old “white” oaks on either side of my driveway. Both have done reasonably well although one has been less productive (sparser canopy) over the past 2-3 years. We’ve had quite a bit of rain this year and I fertilized the tree (at the drip line and in toward the trunk) with a slow release fertilizer called WOODACE 18-5-10. I refer to WOODACE as “steroids” for trees and shrubs. Is it possible that between the rain and fertilizer the tree is “flexing” its bark? When I say the sap is oozing, it is at a very, very slow rate (the crack is not wet). The first photo shows a 3ft level leaning against the tree, the second photo shows a close-up of the crack above the “oozing” point. Any advice or assistance you can provide would be greatly appreciated. I would hate to lose the little guy/gal! Thank you for your time and help,

Calvert County Maryland

3 Responses

The black area looks like slime flux. The wound allows entry by some form of bacteria which causes the sap in the vascular system to ferment and bubble out of the wound. Typically, it flows down the trunk for some distance and will often encourage the formation of a harmless, but unattractive, black 'sooty mold'. This is usually harmless and no control is necessary. See our website for more information http://extension.umd.edu/hgic/slime-flux-and-wetwood-trees-and-shrubs

You can send us more photos if you notice additional symptoms.



Thank you for your quick response. I was surprised to see how quickly you responded! I do not spend a lot of time on emails, just saw this late last night. Thank you, that’s at least one thing that won’t keep me up at night! I have one more unrelated question about a filbert tree that died. Should I submit a new query? Do you folks get “credit -per-query”? Please let me know, I will get back to you much sooner. Take good care and again, thank you very much.

You are welcome.
Please submit a new question as the questions are included in a database.

Once a plant has died, it can be difficult to determine why. It is helpfult to send photos once you notice symptoms so we can see what you may be dealing with.