homenovice, I bought a bunch of different kinds of hydrangeas from JoyCreek last fall. Very cheap and received them in one week. Shipping is pretty much affordable and if you buy more than one you save on shipping. Around $10-12 per plant. Though small shrubs, the root systems are full. They came in pint size pots (smaller than 1 Gallon). Note that they are not big shrubs but good enough to start with and if you are patient then you save money and get all the hydrangeas that you want. http://www.heronswood.com/ has also a good selection of hydrangeas and affordable too.

Unless there is a soil test that indicates that something is missing, stop with the fertilizer. You can create issues with excess fertilizer, both in the garden and in the surface water and groundwater where the excess ends up. As an indication of how much fertilizer this plant needs, in my nutrient poor acid sandy loam soil, without any fertilizer ever, mine has done fine, blooming profusely and taking over as much territory as I will allow it. And regardless, you want to stop fertilizing in August so the plant stops putting out new growth for the year that might not have time to harden off before winter. Do you check to see how moist the soil is before watering? And how long do you water for or how much water do you give it? I would look at the underside of the leaves to see if there are insect pests, but other than quitting with the fertilizer and checking to see that you aren’t over- or under-watering, I would chalk it up to being late in the season, and as a new plant with less developed roots that gets a lot of sun, the leaves are a bit tired. Typically, this is planted where it gets some shade in the afternoon when sun and heat are particularly intense.

Not sure, but the more we investigate the yard the more we are seeing the shriveled leaves on other bushes too! 🤔

Apparently the foliage is getting wet and this is causing a bad leaf spot infestation. Water the soil and never the leaves to minimize the chances of getting fungal issues on the leaves. To know when to water, inset a finger to a depth of 4" and water if the soil feels dry or almost dry. If you water when the leaves are wilted, there is a danger that you are watering too much. The leaves will wilt/droop when they lose leaf moisture faster than the roots can absorb more water. The internal pressure differential causes the leaves to wilt then. Scenarios that trigger this condition: temperatures above 85F; too much sunlight (aim to give them dappled sun or morning sun until 10-11am; no afternoon or evening sun if possible); hot, drying winds; lack of water or lack of enough water; small root system (new plants) or disturbed roots due to transplants. Wilted plants can be left alone if the soil is sufficiently moist (use the finger method to check); they will perk up at night on their own if the soil has sufficient soil moisture. In the hot summer months, I make a habit to visually use the finger method when I see wilting and I water immediately if the soil feels dry. If the soil is moist, I let them be and I re-check in the morning. Somewhere around 6-8am when I wake up, I see if any is still wilted. If so, they get water. If you water just because they are wilting, you may be watering too much. That can cause leaf and bloom fungal problems (as seen in the picture) and-or root rot (if the soil remains soggy long enough). Watering twice a day can sometimes be done in well draining soils but try not to make a habit of it. In the fall, discard all foliage and blooms in the trash as they will contain lots of fungal spores; do not put them in the compost pile. If you deadhead any blooms now, discard them in the tras too. You can also cut off the worst of the leaves but do not assume you will get new foliage quickly while in the middle of the summer (maybe in the fall or in spring). Water the soil only, from now on instead. If using a sprinkler system, water around 6-8am so the leaves do not spend the night wet. Use clean sanitation practices (discard plant material in the trash if any falls down or is left in the fall; water the soil only; do not overwater; prune leaves so plants do not touch, something that can help increase air flow and reduce humidity, etc.) as best as you can to minimize spreading the fungal infection to other hydrangeas.