I don't see any health problems. Blooms can be deadheaded at any time. The shrub looks a bit bare and lanky so probably needs some shaping/rejuvenating. If it was full looking earlier this year then let it alone - maybe it has had a lot of leaf drop recently.

Hydrangea blooms go through a series of color changes as they age. The exact sequence of color changes varies based on the type of hydrangea that one has, the hydrangea variety, the soil and other factors. Your blue blooms stay blue for a while before they begin a series of color changes that usually end in a shade of brown.

At this point, you can either deadhead them or keep them thru the winter months. They will eventually fall on their own. I never deadhead mine and only notice them missing by Spring so, I guess they fall down between Jan-March.

Stems that are completely dried out can be pruned at the base. Those where the top is dried out but the lower half has leaves can be pruned down in 1" increments (or less) until you see green; then you can stop. But I do not recommend you prune those that are half alive now; better wait until April-May 2014.

The reason? Flower buds for early Spring 2014 blooms develop at the end of the stems in mid-July here (same or close where you live) so be careful pruning or you could loose 2014 bloomage. If this shrub reblooms, pruning will result in no early blooms but you should get more around June-ish.

See the link below for more pruning info. See the paragraph titled "REMOVING OLD BLOOMS" for information about deadheading.

This post was edited by luis_pr on Sat, Sep 28, 13 at 10:17