I wouldn't bother treating it. It's not anything serious (those bottom leaves are showing mechanical damage, not fungal issues) and the plant will most likely outgrow it. Often fungicides wreak more havoc than they correct and I am hesitant to recommend them unless the situation clearly warrants it, which this does not. Keep in mind the cultural needs of the plant - does it have enough air circulation, is it getting enough/too much water?

One thing you might want to keep in mind when reviewing your garden is that it is not going to be perfect and pristine - stuff happens in nature :-) If you can stand 10' away from the plant in question and the problem just pops out at you, then you have a reason to be concerned. If it's not obvious at a distance of 10', you are being overly protective. Back off and relax a bit :-))!!

Thanks for the reply! As long as the plant won't be killed by a disease I'm happy to let it go. We had a really hot spell here last week, close to and over 100 degrees for several days. Plus very high humidity. Now it's in the 60's and humid. Normal is 70's and not so humid. I thought perhaps the plant was stressed and more susceptible to disease and didn't want things to get out of hand. I'll just keep an eye on it then!

i live in BLACKPOOL england and have a climbing hydrangea growing against a north west wall, the first year it did not flower but this year it has started to produce flower heads but before they can bloom the stem turns black and rots resulting in the flower dropping off, also the lower leaves have brown spots on them and curl up and also drop off, i have fed the plant with propriatory feeds but to no avail . HELP

Hello, alan. Blooms are one of the first things to be aborted when the plant is stressed: weather issues, has too much moisture, fertilizer, diseases, etc. Do not feed a stressed out plant; instead, determine the cause of the problem and take appropriate action. Determine if the soil is wet and, if it is, reduce watering. Some leaf curling can occur because of cold weather or by the hydrangea leaf curler insect. The brown spots suggest that the bottom area is exposed to high humidity levels which allow the fungal spores to thrive. Reduce watering to see if that helps (insert a finger into the soil & water when the soil feels dry or almost dry at a depth of 10cm). If the infestation is small, it may self-correct as summer temperatures and lower humidity levels arrive.