Is the product Fish and Poop okay for hydrangeas?
It's a slow and fast release formula. I'm concerned about the fast release part as it appears hydrangeas need slow release.
Yes, you can use Fish and Poop on Hydrangeas. Use ½ fl. oz. per gallon of water or ½ pint (8 fl. oz.) in hose-end sprayer. Apply monthly during growing season. Also, be sure to apply in early morning or late afternoon.