Colmnar English Oak Sagging

Asked July 8, 2015, 3:31 PM EDT

We have a group of 4 columnar english oaks in our backyard that are established (30+ feet tall). But since the big storm that came through our area (we live in Superior, CO) a few weeks ago, a couple of the trees have branches that are drastically sagging (nearly touching the ground). I noticed some of the leaves on those sagging branches have small brown dots. Any idea what it would be or how we can fix it? We really really don't want these trees to die.

If there's any more information I can provide (including photos), let me know.

Boulder County Colorado trees and shrubs

10 Responses

Hi

Thank you for your email. We can definitely help, if you could send us photos of your oaks, that would be great. It might be a storm damage, but it's hard to tell without photos.

Could you send us close ups of the small brown dots as well as a zoomed out photo of the branches and the whole tree?

Thank you!

Selina Steppacher


Each of the 4 oaks are sagging to various degrees, and each has leaves with the brown spots to various degrees too. The pictures I attached are of the tree that looks the worst, and has the worst sagging.

Hi,

Thank you for the photos. I would like to gather a little bit more information before we make any conclusions. Are the leaves that have the brown spots on them only concentrated to that one branch or are they uniform over the entire tree and on all four trees? Also, do you see anything abnormal with the bark on the branches or the trunk of the tree?

Thanks for the info and we should have an answer for you shortly.




The leaves with the brown spots appear to be kind of random. There are some main branches that have healthy looking leaves on some branches that are off of that, and leaves with brown spots on other sub branches. And that's the case fro The bottom of the tree up to as far as I can see. As for abnormal branches or the trunk, I don't see anything out of place. Although I noticed that branches are sagging all the way up on especially that one tree.

Hi, Thanks for the pictures. We are looking at so many factors that could be affecting the trees. You can do a few of these things:

1. bring a sample of the tree, both good leaves and bad on a 10" branch to the Extension Office at 9595 Nelson Road, Longmont CO 80501;

2. look for evidence of damage to the bark and the trunk and at the angle where they meet (send pictures);

3. check for any galls or sap or oozing on the trees (send pictures);

4. try leaning on the trunk of the tree to see it is unstable in the ground.

Let us know how it goes and contact us again anytime.

Thank you,

Cathy


The trunk is solid when I push on it, and I don't see any oozing. Here are a few more pictures.

I found a honeycomb-like substance under a leaf, a red mite-type bug, and some dark drops on the underside of a leaf. There are also earwigs and various kinds of spiders on the leaves/branches. Hope this additional info helps.

Your oak trees seem to have more than one problem. Under the microscope we did find some Kermes Scale http://www.ext.colostate.edu/ptlk/1400-11.html which looks very much like a new bud with the naked eye. You can apply a dormant oil in the spring and try a crawler spray early this fall. Otherwise there is not a good means of eradicating the scale except to cut off the areas of damage. On the branch you did bring in, we did observe teeth marks likely made by squirrels who will feed on the scale.

The drooping of the branches would be a separate issue. If you are able to bring in a larger branch sample, we can cut into it looking for Verticillium Wilt which is a fungus we're seeing a lot of this season. http://www.ext.colostate.edu/ptlk/1400-6.html

The drooping could also be caused from the heaviness of the new leaves not being supported by the woody structure of the tree -- so much water this spring! You could do some pruning back to reduce the weight and see if this helps lift the branches back up.

Thanks for taking a look at our trees. In regards to the drooping, which do you suggest we do first: Take a bigger sample of the branch in for you to look at, or prune to alleviate weight. And, if it's better to prune first, when is the best time to do that. We've always heard it's best to prune in fall to minimize stress on the tree. But is that not the case here?

If you want us to take a look for Verticillium Wilt, then please bring in a sample. From the photo provided, it looks as though pruning would be a good idea. Pruning in fall (as opposed to summer) will minimize stress on the tree as the temperatures are typically not as warm and the plant can focus on healing the cut wounds.