Hi Erica, I'm thinking it was a combination of more fertilizer (which they don't need the first year), the insecticide spray, and the sun! Is it possible that he tender leaves did not like the spray on them and burned in the sun! You may have to cut them back and wait for new growth, but no more bug spray and limit the sun until they get used to it. New plants in pots look great when you buy them but they don't acclimate themselves to the elements for a while. I have a bed of 6 hydrangeas in shade most of the day but they get 2/3 hours of sun in early afternoon and this year we added 3 new plants to the planter and the flowers burned to a crisp on the new ones and the older ones that had been in the ground for a year or so sailed through the heat and sun with no problems! The temps went up to low to mid 90's for several days, and all the hydrangeas in my yard wilted from the heat but the flowers perked up in the evening. Don't be afraid to prune them back if necessary, it will thicken the plant for you and you should still get some blooms later on the remontant types. Good Luck! Donna

Bobo has become my favorite hydrangeas for the last 2 years. I have 2 planted in a full sun location in the fall of 2013, as 2 quarts (~ 1 ft tall) small plants ordered online since local stores did not carry them yet. Both gave nice and long blooms in 2014, and have been doing great ever since. The size is much more compact (~ 3'x3') so this is a big plus for my small chicago area lot. In spring time, I only sprinkle a little bit (1 tbs per palnt) of Miracle-Gro® Shake 'N Feed® All Purpose Continuous Release Plant Food. There are several kinds, I use the one with NPK 10-10-10. I don't typically use fertilizer but rely mostly on mulching well. I agree with NHBabs that these H. paniculatas need to have more sun for best performance. Mine is planted in the same full sun bed with cone flowers, Phlox and black eye Susan. I almost never water them so Bobo endures the summer heat and drought just as well as cone flowers, etc. I did notice that my neighbor's little Lime blooms much less as they are in a partial shade locations than my limelights (full sun). I understand the fun sun in zone 5 (chicago) may be different from other areas.

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.

Yes, you can grow ES hydrangea in full sun under the right conditions. It is not the summer sun they mind as much as the heat. In direct sun with the heat, they will likely wilt during the day and perk back up in the evening. A little bit of that kind of stress won't hurt them much as long as you are not in drought conditions. The red leaves may be a feature of the particular cultivar you have. Some of them do have a reddish tint to them that can be highlighted due to environmental conditions. Planting any shrub too close to the house is bad form and not a wise move. Limelight is a much larger shrub than an ES hydrangea and not likely to be a good alternative for most foundation plantings. Your biggest problem with a H. macrophylla cultivar in your zone is going to be late spring freezes. If they break dormancy in an early warm spell and then get frozen to the ground, you will lose that year's bloom. They bloom on older wood and don't have enough time to regrow and bloom in one season of growth. In my southern zone 6 that warm then back to freeze cycle is common and H. macrophylla to a large extent have one good bloom year out of four. The key is they cannot get frozen after breaking dormancy in the spring.