Leaves turning yellow on redbud

Asked September 6, 2017, 1:21 PM EDT

I have a redbud tree whose leaves are turning yellow and falling off. While I know this is normal in the fall, the neighborhood trees planted at the same time are still green. I have attached pictures, the one that concerns me most is the base of the trunk which appears to have been hit with what I suspect is a string trimmer. Could this be the cause of the trees distress? I appreciate any help/info you can provide.

Clackamas County Oregon

8 Responses

Thanks for your question about your redbud tree. First, a link to a short Purdue Extension article about mechanical injuries to trees, which I recommend you read, regardless of the yellowing leaves, because you're going to have to monitor the tree for safety issues. It appears that you have mulch around the tree, but extending this even further may reduce the risk of creating (or re-opening) a wound in the future.

Now, as to the leaves. Premature leaf yellowing (i.e., before fall) typically relates either to a lack of water so the plant can absorb nutrients, leading to a nutrient (most notably nitrogen) deficiency. Plants need 3 essential nutrients in great quantity to photosynthesize, and if those (as well as 13 micronutrients) aren't available, the leaves become chlorotic (yellow) and die. So, perhaps your watering habits were different this summer than your neighbors' and their trees are not dropping leaves as early. You can still provide supplemental water to your redbud until the rains return, but you should monitor your tree next spring for signs of fungal infections (brown spots on the leaves), and add some balanced (10-10-10, for example) fertilizer and regular watering next year.

Do be sure to pay close attention to safety issues that might develop due to the mechanical injury! Hope this is helpful. Good luck!

Sorry, I was just about to edit this to include it gets watered every day, so drought isn't the problem. I'll review the link you sent. Thanks for your speedy response.

There won't be anything in the Purdue link that deals with yellow leaves, directly. I have a request of you: could you please take a photo of the leaves that haven't all turned yellow, so I can see what the veins look like? From what I can tell, they seem to have green veins, and the tissue between the veins is mottled, and a few have dark spots. All indicative of different things. Thanks!

Here you are. Again, I appreciate your help.

Great! Just running out the door, but I'll send some analysis when I return! Thanks!

Looking at fast clock. Check out this article and, especially, compare the leaves in the plants pictured there, with the photo you just sent me.

Thanks. I'll see if I can find some fertilizer with iron.

I'd suggest you buy a cheap pH tester (or litmus paper) to see if your soil is alkaline, since it's the pH that impacts whether the plant can absorb already available nutrients.