Regarding the oakleaf...do you have deer or any other animals in the area that could be browsing on it? They did that to mine after planting them 4 years ago. Since then, I have protected the oakleafs with barriers and they seem to have finally gone gangbusters this year, and look so much better/healthier. If not deer, it could just be a transplant shock/problem. Try leaving it where it's at and maybe give it some mushroom compost and water regularly this season. I have heard that Oakleafs take their time getting going, and I can attest to that. The last 4 years mine looked scraggly and sad. Give it some more time. I am 99% sure that I have also fed mine Holly Tone, for acid loving plants. That may help too.

Looks like a bad case of leaf spot, pcorn, usually caused by overhead watering and humid conditions. Try to minimize the return of this fungal infection by never watering the leaves. Instead, water the soil early in the mornings, discarding plant debris, the spent blooms and leaves to the trash, replacing the mulch with new mulch and, if it fits your budget, apply fungicide as described in the link below. See the information on Cercospora Leaf Spot. Here is a link that might be useful: ACES Diseases of Hydrangea

It may just be preparing to shut down for the end of our very long growing season. Only God knows when the wholesaler forced it to leaf out... usually they pick rather early & abnormal times so the plant looks nice in store shelves by late March or April. As a result, your shrub may just be reacting to reduced light leves and slowing down. As our very long growing season starts to end, previously greenish stems begin to transition to brown colors as they harden and prepare for winter. Some hydrangeas do this before others. Some do it more brownish than others. I can't speculate much on what else happened while it was being cared for by the coworker. Leaves on some of my hydrangeas recently turned light green so I amended the soil with acidifiers (greensand and aluminum sulfate that I had handy); other leaves are showing signs of drying out but the plants always do that as they are getting ready to shut down so, unless you see new issues, I would not worry much. Consider that too much watering causes root rot which makes leaves wilt/droop continuously 24/7 and your plant's leaves look mostly fine. I said mostly because in picture 3, I see one leaf that may either be dirty, has some mite webbing on top of the leaf or has a touch of powdery mildew -- see the grayish color on the top of the bottom large leaf on the right side of the main stem. I could not clearly tell which of those possibilities but -good news- this issue was not in other leaves. If it is PM, it could be the result of overhead watering so water the soil instead of the leaves. You may also want to check the soil pH too in case that explains the leaves turning light green. It is a common problem in potted/often watered hydrangeas. Or it could be that the leaves are just getting reading to dry out as the plant shuts down between now and December. This newly purchased shrub will n-o-t be in sync with the other ones that you have this year. So do not worry but keep an eye on it. Post again if another symptom(s) develops. Lastly, I would add a small layer of organic compost so the water & soil moisture last a trickle longer in the pot. It will also supply some minerals as it slowly decomposes. Enjoy the new purchase! Luis

If last year's stems fail to leaf out and all growth in Spring comes from new stems, this hydrangea may require winter protection to bloom reliably. It probably develops invisible flower buds in late Summer or early Fall at the ends of the stems. These buds should then open in Spring but, if it gets too cold and the stems get killed, you get no blooms. Winter protection in the Fall would help with that. I put chicken wire around some of my hydrangeas and fill the inside with mulch. A few weeks after my average date of last frost, I remove the winter protection and use the mulch elsewhere. If you are pruning it at some point, consider that the invisible flower buds develop in late Summer or early Fall but they then open in the Spring. Thus it is best to prune no later than the end of June so no flower buds are pruned off. If you have any old stems in Spring that do not leaf out by the end of May, prune these all the way down by the end of May.