Some chemicals found in fungicides or insecticides can make hydrangea leaves curl, specially new, small, sensitive foliage. And some tiny pests like spider mites can also make new growth curl. Did you look for tiny pests or did you look elsewhere (in branches, in the soil, under rocks, etc.)?

How come you are are using fungicides so early in the growing season? Where are you located and what type of hydrangeas are these? Also, did something happen at about this time last year?

I live in Georgia and had a huge problem with fungus last year all over my garden and started spraying too late. :( I don’t think was soil born because it appeared to start with the zinnias, but I guess I’ll find out. But perhaps I should leave the hydrangeas alone for now?

These are typical ball hydrangeas and I don’t recall anything happening last year. I looked on the leaves and stems. But I haven’t looked in the soil (it is clay) - what would I be looking for?

Yes, I would instead keep the foliage dry when watering (water only the soil, never the leaves) and hold the fungicide until it is needed with the hydrangeas (post pics as soon as you see something). There are insects, worms, caterpillars, larvae that can be pests and feed off the foliage. And these pests like to hide under the leaves, rocks, in the soil. Many of these guys appear only at night so it may be a good idea to check in the evening too.

Thanks!