It has been watered regularly via drip irrigation. Mid June I did fertilize the shrubbery around this Hydrangea but was careful not to get too close... this is the only thing I can think of that caused this. As a general rule I don't spray anything outside... so nothing could have landed on it.

We planted this hydrangea late May/Early June. A little late for the southeast, but we also planted two others in another part of the yard and they are doing just fine.

It may just be that the planting location for this one offers different conditions than the others - more sun, different soil, etc. It could also be demonstrating some stress from the original planting. Like the rootball was not properly disturbed before planting or was allowed to dry out. Sometimes if the rootball is very dry at planting time, it is nearly impossible to hydrate properly once in the ground. You might want to poke your finger down well into it and check.

But these are pretty tough plants all in all and I think it should come back next season just fine. Just make sure it gets a good deep watering if necessary.

Since this is happening so close to summer, I agree that it is likely a combination of not enough water and sunscald (I give shade to mine starting 11am-12pm or earlier) but, also check to see if you have a mite infestation as they can cause leaf damage that looks similar to the brown leaf sections.

And add a smidgen of iron in the form of greensand, sulfur or aluminum sulfate as some leaves look chlorotic.

Fall is not helping diagnose since oakleaf leaves down here start to turn orangey-brown-ish too. Maybe that is also starting where you live as well. However, they will be fine next Spring.

Make sure you do not feed too much fertilizer as that too cause a burn look on the leaves. Since it was planted this year, it probably has those round fertilizer pellets and if you fertilized after planting, it probably got too much. Hydrangeas are not heavy feeders so just feed them once in Spring (1/2 to 1 cup of cottonseed meal, composted manure or organic compost a few weeks after leaf out). You can also add coffee grounds, liquid seaweed or liquid fish thru the growing season but stop fertilizing at the end of June so the plant will not stay in grow mode as early frosts arrive in the Fall.

Here is some reading information:

http://gardening.yardener.com/Problems-Of-Oakleaf-Hydrangea

http://homeguides.sfgate.com/dry-brown-leaves-hydrangea-69182.html

How much sun does this plant get? I think that in your zone in the SE, oakleaf hydrangeas appreciate a fair amount of shade, though bright or dappled is best.

The plant gets about 4 hours of direct sun from about 11-3pm, otherwise all shade. Thank you all for the feedback!

4 hours in the middle of the day seems enough to burn a plant that needs some sun protection.

Good to know... I will find a way to get more shade or move it to a different part of the yard.

Morning only sun or dappled sun are best tolerated by plants that prefer part shade.

Late in the season, the leaves on many hydrangeas will develop and suffer from a host of issues (about 2/3 of mine have damage from fungi, bugs, and other diseases), especially nursery-grown plants that got a head start on the growing season. Most issues will "reset" after a few winter freezes. Next June you'll likely not remember anything was wrong with the plant. By this time of year, the plants have shifted energy into bud production for next year. Long as there are healthy looking stems with buds at the leaf nodes and on the branch tips, the plant should re-grow just fine next season.