I have not dealt with rust in hydrangeas before but I have seen recommendations that include replacing the plant (dispose in a plastic bag if possible) or using fungicides with these active ingredients: mancozeb, myclobutanil, propiconazole.

Note: I have not seen these ingredients specifically suggested for hydrangeas so I do not know how well they will work or what dosage to use. Check the labels for directions or call the manufacturer to see if they have specific dosages for hydrangeas that are not listed on the label.

If the fungicides that you already used contained one of these ingredients, I would cut my losses and get another plant from a different source.

Other suggestions... avoid overhead watering and water the plants in very early in the mornings using drip irrigation or soaker hoses; improve air ventilation in the area; discard fallen hydrangea leaves instead of adding them to the compost pile (if you have one). Finally, I would replace the mulch around the infected plant too (in a plastic bag) since fungal spores may be found in the top of the mulch.

The link below shows some fungicide recommendations from the University of Tennessee.

Good luck, Luis

Here is a link that might be useful: Rust Fungicides

Thanks for the response. I went back to the place I bought it and was just browsing for other things and then noticed ALL the hydrangeas left had the same problem! If it's airborn i hope it doesnt spead to my other plants. Needless to say, I didnt buy anything from them, and won't again.

Thanks again!!!
Jacki