Hello, roseabbey. If you experience lots of showers at the end of the growing season, it may be worth applying c/s since the showers will increase the spread of the disease. Otherwise, you could try to determine if the expense is worth it since we are near the end of the growing season. If you already have c/s and the shrub looks like it needs some help, I would apply some. If the shrub is in a very visible location, I would apply some. But if it is a big expense for you and the shrub is just ok then apply it in next year. I suggest making a note of when the problem was first seen this year (typically it happens in late Summer or early Fall) and then begin applications one month earlier in 2012. By the way, watering the soil and not the leaves will definitely make the fungus very very unhappy. Hee hee hee!

Luis

Hi Luis
Thanks. I have about 35 hydrangea plants, different varieties thank goodness not all of them have fungus, I think about 12 plants have fungus. I have learned not to water overhead if possible. I did put down soaker hoses where I could but some of the hydrangea are watered with sprinkler system and those are the ones that have the problem. If I do spray them now with c/s would I only spray one application?

No, most likely the product label says something like "as needed" and gives you an interval that varies. So it would be applied -for example- every 10 days as needed; every 14 days as needed; etc.