Many (although not all) hydrangeas do not like afternoon sun. Am sun/pm shade. I can't tell what those variety are but they look like the kind that do not like afternoon sun from the photo. Try moving to appropriate lighting, water lots, especially if hot.

Little Lime Hydrangeas are paniculatas and these tend to "show their feet" by yellowing leaves in the summer months. They are extremely sun tolerant compared to other hydrangeas and can take full sun in many places but may benefit from a tad of shade in the late afternoon hours in the South. The move from the plant nursery to the home may have changed the environment enough to trigger this (water, sunlight, heat, etc.). Remember to mulch well since we are in a sometimes inhospitable ;o)) time of the year for planting hydrangeas. Consider acclimating them slowly from shade to sun. And water at "Summer" watering levels. Fertilize next year per label directions as the slow release fertilizer should be enough for this season (unless you are in Florida or the extreme south end of the southern states). Do not fertilize when the soil is dry in order to minimize the chance of fertilizer burn. Osmosis causes water to flow out of the plant when you fertilize and the soil is dry. You can also use about 1 cup of organic compost, composted manure or cottonseed meal. A general purpose, slow release, chemical fertilizer with a NPK Ratio around 10-10-10 in Spring should be enough.

Plants in nursery containers will require daily watering in summer just about anywhere. And in some cases, even twice a day! The yellow leaves are due to lack of adequate water, not disease and not fertilizer burn.

btw, Hydrangea paniculata, which is what Little Limes are, are the most sun tolerant of any hydrangea species. In most areas they will grow happily in all day sun if provided with sufficient water.

Thank you! I will be more careful watering them until i can plant them, and the drip can take over then. The bed I want them in is right next to a construction zone nearing completion and I dont want them stepped on. They will be planted in morning sun, afternoon shade

Where are you located Marble? in my central NH location they are happy with all day sun, but for Luis in TX, afternoon shade is best.

Over-watering can cause yellow leaves too, so be careful.