I will also mention that this is a new planting bed created a little over a year ago when I had a sienna Glenn maple moved in with a tree spade.

The leaves look a little "rugged", like the soil dried a little then got some water then dried again so I would suggest trying to aim for the soil being as evenly moist as you can. too much sun and high temps can do similar things. To keep the soil evenly moist, either use a soil moisture meter or use the finger method: insert a finger to a depth of 4" and see if it feels dry , almost dry, moist or wet. Do this early in the mornings for 2-3 weeks. When the soil feels dry or almost dry then water the shrubs and make a note in a wall calendar. If the soil feels most or wet, do not water. If the soil is wet, research why (did it rain recently? did the sprinkler go on? or is there a problem? etc). Each time you water, make a note on a wall calendar and after 2-3 weeks of testing the soil daily, review on average how often you had to water (every 2/3/4/5/days for example) Then set the sprinkler to water the plants every 2/3/4/etc days and recheck with the finger method for 2-3 weeks again if the temps change 10-15 degrees and stay there or if the weather is different (has not rained for a long time or is raining a lot, etc). Maintain 2-4" of mulch to conserve soil moisture and make waterings last longer.

Something is eating the leaves but you must find/confirm what it is before applying chemicals. JBs sounds like a good possibility; they leave mini bite marks on the edges of the leaves mostly but really, any part of the leaf is ok for them.

In many cases, the culprit has done the damage and left or the culprit is hiding under rocks and only comes out at night. Insecticides and fungicides could damage some hydrangeas so please be careful and take action when you know what the culprit is and if the spray will help control the culprit. I suggest that you "visit" the shrubs multiple times thru the days and nights to see if you find something munching on the leaves. Look under leaves, rocks and plant debris. Then take a picture and post it if you do not know what the insect/etc is. There are some beneficial insects that are good guys and other insects/worms/etc that are not.

I am not sure what the yellow spots are. They were not clear enough in the pics but I wonder if you can take closer pics of them. As well of the same spots in the maple leaves.

Eventually though, the leaves will start looking a little sad at the end of the first growing season. You bought these guys in the Spring but they may have been awakened "early" by the plant wholesaler so the shrubs are fully leafed out and maybe have blooms when put on sale at retail. So the leaves are probably getting "old" too; do not panic. This may just be a first year, kind of a thing rather than a death warrant. ;o)

Remember that their root system has been cut to fit into the pots and is tiny and unable to fully help in dry conditions so it is imperative to let Year 1 plants develop a good root system, especially plants that like water as much as hydrangeas do.

I agree with pretty much all of luis's comments :-) I see NO sign of any disease - only some insect issues. That darkened, brown portions of the leaves are only necrotic leaf tissue indicating that the insect did the damage some time ago so may not be present now.

It is not worth treating for at this time. First, I doubt the culprits are currently active and still present; second, the plant will be entering dormancy soon enough and losing all its leaves any way. And finally, insect issues on leaves are more often than not just cosmetic and cause the plant no permanent harm. WE don't like the looks but the plant doesn't really care :-))

FYI, but it is extremely rare that a tree disease - like maple tar spot - will infect some other species of plant. It just doesn't work that way. Plant diseases do not run through a garden like a plague - they are restricted to certain plants. Whatever might be bothering the maples will have no impact on the hydrangeas.

For first year plants, they are fine. Maybe not looking as great as they could but still healthy and growing. Just let 'em be.

Thanks for the advice! I've got about 3" of dark mulch in the plant bed currently. Sounds like I'll need to be patient. I plan on cutting them back a bit this fall but not all the way to the ground.

Where are you located? That's an awful lot of sun for Hydrangea arborescens. I would say sun stress is accounting for much of the foliage issues. Hydrangea paniculata cultivars might be better suited to that location and move the Incrediballs to somewhere where they can receive some shade in the afternoon.

Hi treygalaxy, remember that Incrediballs can get quite large...in that area I don't know , 7 seem like a lot.. I have about 5/6 around the yard that are in sun for a good 6+hrs...when the rain comes that's another story

Trey, that one on the end of the bed (furthest from tree) definitely has a fungal issue. Happened to one of my Incrediball in year 1. By the end of next month, the leaves quite possibly will be totally gone on that one. It will hence be a bit retarded and will need to "reset" in over winter and "restart" a rudimentary way next spring. There's not much that can be done now, but any leaves with brown crispy parts should probably be removed or else it will spread around the plant (from the bottom up).

To me, yours don't appear old enough / tall enough to hack down much in the off-season. After 2 more years that will change. I keep my pruned stem heights to around 18" and also take care to remove any dead wood (there will be a few) that crop up each season.

Also, I'm sad to report the Beatles are no longer out. (sorry couldn't resist!)

I just brushed a Japanese Beatle from my shirt yesterday. Positive it was that beatle & no other. Anyways I planted them in that location because I wanted something that could create some height & look beautiful for some privacy from the street. My local nursery said they like sun & shade. With my maple tree only going to get larger in the future (Sienna Glenn variety) I figure it could be an alright location. But I'm starting to think I made a mistake going with hydrangea in the first place. I'm in zone 4 south central Minnesota.