Yellow and light green leaves on my hydrangea

Asked July 27, 2019, 9:48 AM EDT

Hi there, My big, beautiful strawberry cream hydrangea have yellow leaves, mostly "inside the bush" currently, but I noticed a whole bunch of other leaves are light green and some have these brown spots. Is this Iron Chlorosis? How do I treat it? My husband just treated the side walk weeds with a weed killer a couple of weeks ago. The side walk runs alongside these bushes, but he got pretty close to the weeds, so I don't think much floated around. Thanks for your help! Pics attached.

Dakota County Minnesota

1 Response I prefer using ammonium sulfate because use of aluminum sulfate can cause aluminum to build up in the soil. New leaves aren’t affected so herbicide damage is unlikely.