It is ok to deadhead spent blooms and to cut off the dried out stems in late May.

The plant appears to produce lacecap blooms and the blue color may have been caused by amending the soil with aluminum sulfate to acidify the soil and make it easy to uptake aluminum (which is what makes the blooms a shade of blooms. You can begin a program to amend the soil with a/s and try to maintain it at the rates suggested in the a/s label but do it forever. If you stop then the soil will slowly revert back to its normal state and the blooms will not be blue. Try not to exceed the recommended levels by too much as too much Sulfur may burn the small roots.

There are some highly yellowish leaves on the first picture but they were too far away to 'see' them clearly. Leaves will turn all yellowish -including the leaf veins- if the plant gets too much sun; only leaves in direct contact with high levels of sunlight will be affected and the ones underneath will be their normal dark green.

However, if you see that the yellow leaves have dark green leaf veins (which gives the leaves a skeletonized look) then that is a problem called iron chlorosis and adding aluminum sulfate will help with this.

The last picture had one leaf browning and a few missing pieces. If you see that m-a-n-y more browning from the edges inwards, that means the plant needs more water. Normal to see this in the Summer. But in general, I did not see this elsewhere so, the plant is doing well. Perhaps add some mulch to make sure this does not become a problem. Add 2-4" up to the drip line. If the pieces of leaves that are missing were caused by the pooches then I would not worry. If the pieces missing were caused by insects that have already left and these is no increase in the number of damaged leaves then I would not worry either. If the number of damaged leaves increases then I would look for pests during the day and during the night. That included checking for slugs, etc.

The middle picture showed a leaf still green with some lesions that were too far away to identify. Maybe just dirt and water mixed in. Maybe not a problem. Maybe the result of the pooches causing minor leaf injuries. Basically, I would not now worry unless I see the same thing spreading to a large portion of the upper and lower leaves too.

Here is more info about hydrangeas:

http://hydrangeashydrangeas.com/

Luis

Where are you located? Around here, those would be fairly stressed looking plants.

If the dogs are peeing on the shrubs at all, give the shrub a really thorough watering immediately afterwards since the concentrated nitrogen and salts in the urine can damage plants. If it's been dry where you are, give the plants a deep watering when the soil feels dry a couple of inches down. They also would appreciate a good layer of an organic mulch such as shredded bark or leaves.

If you want the dogs to not play in the shrubs, often a low fence (one of those ornamental wire fences less than 1' tall) around a plant will help train pets to avoid the area, and as the shrub fills back in, it will hide the fence.