I am posting another picture of the leaves close-up.

Hello, AWB_1980. Looks like a fungal infection called cercospora leaf spot. Hydrangeas that get overhead watering or that live in humid locations can develop this disease (see the link below). Very common in late summer and early Fall.

At this time of the year when the shrubs will soon enter dormancy, you may want to use good sanitation techniques to see if they help at around this time in future years. Some example of things that you can do: water the soil (never the leaves) early in the mornings from the base of the plant outwards; do not overwater as high humidity helps fungi develop; dispose in the trash of any plant debris under the shrub; similarly dispose of the leaves and blooms when they have dried; replace the mulch with new mulch if it is a big infestation; allow for some separation between the hydrangea and nearby plants (this allows air to dry out the leaves quicker).

There are recommended fungicides in the link below which you can use at the first sign of spotting. Some of the products can be expen$ive so consider the good sanitation techniques first. Cercospora leaf spot will not kill the plant; it is just an "aesthethic problem".

The stems that appear dried out with no leaves in the first picture can be pruned now. In Spring, you may want to wait until May to be sure that they will not leaf out; if the do not, then prune them. I also noticed no mulch; feel free to maintain 3-4" year around.

Fertilize once a year using a cup of compost, composted manure or cottonseed meal. During the rest of year, you can also add some coffee grounds, liquid seaweed or liquid fish.

Luis

Here is a link that might be useful: Cercospora Leaf Spot

This post was edited by luis_pr on Fri, Sep 6, 13 at 9:35

Luis,
This hydrangea looks a bit "leggy" in its growth ....would you recommend cutting it back to re-shape the hydrangea into a more compact, full looking specimen?
Just curious.....

You can do that. It is less stressful if you do it over the winter months. If you do that, it may -at worst- cause you to skip bloomage next year. Depends on what hydrangea that one is.

Thanks for the advice. I have been ensuring that I pick up all leaves/debris that have fallen.

ians_gardener, what do you mean by leggy?

luis_pr, you're correct in that there currently is no mulch around the plant or the rest of the garden bed. Two owners ago was known as the guy with the gorgeous garden, and the previous owner was known as the guy with the big sheepdog who ruined the gorgeous garden. We had to define the garden bed earlier this year, and will be putting down a layer of peat moss this weekend, and mulch over the next two weekends.

For the record, I believe it is a mophead hydrangea. My aunt recommended that maybe we cut back sooner than next Spring. If a non-blooming hydrangea leads to a healthy hydrangea, I'd rather have a healthy, non-blooming one for one summer than a sick, blooming one for many summers.

Thanks again!

Hi AWB_1980 .....

I was meaning that the canes of your hydrangea are long and only really have foliage at the tops of the stems.....most healthy hydrangeas are quite bushy.....so much so that you cannot see through the shrub like you can with yours....by cutting it back, it will encourage more stems and a fuller looking shrub, but as Luis stated, it is the wrong time and doing so, you will not have the blooms next year
Here is a pic of mine......leafy to the ground.....