Mysterious die off of trees and shrubs

Asked August 11, 2017, 7:29 PM EDT

Something seems to be slowly killing off trees and shrubs in 1 portion of my yard and adjacent neighbor's yard. They seem to die off one by one. This has happened over a period of years and affected conifer shrubs and trees, a madrone, manzanita, holly, lilac bush and now a large oak. There are no visible pests that I can see. What is it and how can I stop it from destroying more trees and shrubs?

Jackson County Oregon landscape plants

5 Responses

Thank you for your question about your landscape plants. It is impossible to detect a cause without photos of the plants, both from a distance and closeup. We need pictures of the leaves, trunks and stems to see what seems 'wrong.' Can you explain what is happening with more specificity? There are fungal diseases in the soil, but some don't hurt conifers, and others kill anything. Looking forward to more info!

Hi Kristena,

The leaves or needles of the plants just turn brown and die. Although in the case of the big oak, it was different. Last year it seemed to leaf out much slower than another oak nearby. This year it sprouted buds but never leafed out. I'll attach some photos for you.

Thank you for the photos. The tree trunk on the left appears healthy. The growths on the middle tree (I can't tell what type of tree it is) appear to be lichen, which won't hurt your tree. The tree on the right apparently is, in fact, dead. Unlike animals, we can't do autopsies on dead trees, so it's important to ask for a diagnosis while we still have a live patient. You can leave this tree until next year to see if it revives, or you can remove it and either let that area remain bare for a couple of years, or try planting a plant of a different species. That way, if there is something in the soil that is destroying your tree(s), it might not attack the 'new' species.

If you have plant problems in the future, please contact us while Ask an Expert or your county Extension office, but do it while the leaves or branches are showing signs of distress or disease, so we can diagnose the problems as they are happening.

I'm sorry I can't offer you better assistance. Good luck in future gardening!

The tree trunk on the left is the oak that seems to be dead. It formed buds this spring but never leafed out. Is there someone in Jackson County that you would recommend to come out to do a more thorough diagnosis and who could treat the area to prevent further die offs? Thanks for your help with this.

I do not know anyone in Jackson County who can do an onsite evaluation, but I suggest you call the Extension Office ((541) 776-7371) to see if they have any suggestions. I'm sure they'll be helpful!