Oak Tree

Question: For a number of years, we have seen the oak tree leaves turn brown, as you can see in the pictures.  I believe the tree is a Burr Oak. Tree companies have not been able to solve it so I wonder if you might have a suggestion as to what is causing this and what we can do about it.  Thanks.  John

responder: An Ask Extension Expert Replied July 31, 2024, 7:31 PM EDT
response: Hi John,  Sorry to hear about your tree challenges and thanks for sending along photos - that's always helpful! To aid us in understanding the problem, would you be able to give a little more information: How long has the tree been planted? What is the current watering regimen for it? When did you first notice these symptoms? Are you seeing the symptoms on the whole tree or only on some of the leaves?   It would also be helpful if you can send a few more photos of the tree including one further away so we can see the surrounding area and get an idea of where it's planted.   If you would like: you're able to drop off sample at the extension office for our diagnostic team to look at. The cost is $7, and an ideal sample is an 18" long branch (if you can) that contains both good and bad leaves. Our address is 9595 Nelson Rd, Longmont and we are open Monday to Friday from 8:30 to 4.  In the meantime, here's an article from the Minnesota extension that details potential causes of browning of leaves on oaks. What you may notice (and where it's helpful to get more info about the tree) is that there are several different issues that manifest with similar symptoms: https://apps.extension.umn.edu/garden/diagnose/plant/deciduous/oak/leavesbrownedges.html  Thanks for reaching out! The Boulder County Extension Master Gardeners

responder: The Question Asker Replied August 01, 2024, 11:06 AM EDT
response: Additional photos are attached. The symptoms are on the entire tree. The tree is probably 15+ years old and could be 50’ tall. It is not on our irrigation system. However, there are other bur oaks next to us which don’t get watered and they are fine. I have had the tree feed, by root injection, to no avail.   I hope this information is helpful. Thanks again and I look forward to hearing from you.  John     On Jul 31, 2024, at 5:31 PM, Ask Extension <<personal data hidden>> wrote:

responder: An Ask Extension Expert Replied August 06, 2024, 12:03 PM EDT
response: Dear Mr. Rosenbloom, Your question and pictures were sent to our team. Thank you for the pictures. The leaves look consistent with Oak leave Blister. Please read the information given.  https://planttalk.colostate.edu/topics/insects-diseases/1449-oak-leaf-blister/  The damage is done and it is cosmetic. It is important for a thorough leaf fall clean up as the fungi is present in the fallen leaves. It is also important to water the trees in the root zone as the trees are stressed and this will help to keep the trees healthy.  It would also be good to remove the mulch you have against the tree bark. This can lead to moisture damage at the base of the tree and lead to root root.  Thank you for your question,  Boulder County MG Diagnostician

responder: The Question Asker Replied August 06, 2024, 3:24 PM EDT
response: This is very helpful. Thanks so much. John  On Aug 6, 2024, at 10:03 AM, Ask Extension <<personal data hidden>> wrote: