Question
Hello, I have a 3 year old pin oak that has rusty, yellow, wilty looking leaves.  What is this and what can I do to save this tree that is on the Sunny side (West side) of our house?  I did apply Scotts brand fertilizer and weed killer to the grass around the tree in May, I wondered if I got too close to the tree when applying it.  Do you have suggestions?
Thank you.
Nichelle

Answer
Using any product that contains a feed and weed combination can cause major problems with trees. The 'weed' part contains a herbicide that in enough amounts can kill the tree. Certain broadleaf herbicides, such as dicamba (found in several weed-and-feed products) and triclopyr can be absorbed by tree roots growing in lawns and may injure trees if applied too close to the tree drip line.
The roots take up the herbicide and are killed and the result is a browning of the foliage. The roots extend out about 1 1/2 times the size of the crown of the tree so any application within that area can effect the tree.
About the only thing that can be done is water the area under the tree with a lot of water to try and dilute the effect of the herbicide. I would water each day about 1 inch of water for a week and then every other day for a week and see if the tree responds. Put a pan under the tree and turn the sprinkler on and when the pan has 1 inch of water in it stop.

In the future use a fertilizer only and then spray the weeds with a liquid herbicide for lawns. This will be a contact herbicide and will not effect the root system of the trees.