At this stage and at this time of the year I wouldn't bother with a cure.
It will all go away next year.
As a cultural measure you may want to reduce overhead watering in favor of root watering. That's it.

If I bought a small plant with several leaves having these same looking spots, will it spread to my other hydrangeas and will it come back again next year on this same plant? Or is it a one time thing for the plant, depending on if I water overhead? I saw a hydrangea that I'd really like to have that has the same spots on maybe six leaves. There are a couple of leaves that have fallen off into the pot with the same spots as well. I just didn't want to buy a problem. The garden center has three of these small hydrageas (all have the spots) but I didn't see it on any of the other hydrangeas there. Thanks for the help!

Hello, mohicansong. Difficult question... It depends on several things... like, how many invisible fungal spores have spread into the plant leaves, soil and stems. These spores can germinate and spread the spots further.

It also depends on the weather in your city and garden. If the plant is kept under humid conditions (because it rains a lot there, because the plant leaves get sprayed with water a lot, because the soil is kept too wet, etc) then the spores can flourish and spread.

Finally, it also depends on the actual type of fungus that is causing the spots. There are some minor fungal infections that we can live without, specially once the summer arrives and the weather is drier. But other infections, like cercospora, re-occur every year and can be a chore because you can only treat them, not cure them.

If you want to get one of those plants, I would try to get the nursery to give you a lower price since the plants are no longer in optimum condition and either they (or the wholeseller) caused the fungal infection. Since it is a risky buy, the lower price will compensate you for it.

What you can do next is try to minimize the possibility of further development by the spores. Water the soil and not the leaves. Replace mulch that may be contaminated with spores. Separate the plant from others so there is good air movement (which will makes things drier for the spores). Water only when the soil feels dry. Any plant debris (leaves, blooms, etc) should be thrown into the trash and not composted.

Either way you decide, good luck.
Luis

Thanks so much for the input. Not worth the chance of a major problem that I don't already have (so far).

I am totally knew to Hydrangeas and just posted some guestion about climbing Hydrangeas but I also have new other pink Hydrangea,I got couple of months ago and mine developed something like in the picture above. It also had this white fuzz like thing on it and the leaves were brown and all just about gone. I didn't want to put chemical on so I use my coffee grounds from espresso,mixed it w/ couple cups of water and few drops of dishwashing detergent. I poored it over the plant making sure it gets under the leftover leaves. Now month later, the plant is growing like mad. I guess I got lucky. I usually kill many plants before I learn what to do w/them. I hope I don't kill this one.

Before developing a full bloom, the flowers turned brown and each individual bud is falling off. The leaves are fine and look real healthy.