Hello, Houzz user. You did not say if these were planted this year or are well established, if there are watering or wilting issues so, I am assuming they are new shrubs.
Sunlight: I would aim for sun in the morning hours only; shade in the afternoon and in the evening hours. Or dappled sun. The further you stay away from direct 12pm sun, the better. It is too strong, makes you water a lot and the temps get too hot for these guys. I aim for shade starting at 11am, as best as I can though. I even have few in full but bright shade. A few hours of early morning sun does not impact bloomage much.
Light summer winds can make those large leaves loose moisture slowly and steadily in the summer. If I have a windy location, I look for an alternative location before planting them there. Remember.... we are windier than Chicago.
If the plants were in obvious distress now, I would transfer them into pots, keep them in pots until they go dormant in December and then plant them somewhere where they get less sun.The reason? I never plant or transplant anything here after mid May. Hydrangeas begin to suffer from wilting episodes and watering issues as temperatures top 85F and mid-May is about the time when we hit the 90s.
Observations: The leaves appear to be in "ok" shape. Meaning they are dark green and with no signs of browning from the edges inwards. That browning happens when they do not get enough water for a long enough time. I do not see signs of iron chlorosis (the leaves turn light green or yellow with the leaf veins remaining dark green). I see no signs of wilted leaves, although who knows... you may be having to water them every 5 minutes during the day or faster ;o) If you have been watering a lot to maintain this look, then I would consider them stressed enough to move. Specially if wilting is making you are water daily.... or more often. The shrub in the middle has some leaves that appear to have some browning. Could be lack of water or too much sun. It was not clear.
I see evidence of soil recently watered in the picture so I thought I would digress and tell you what I do watering wise.
Use organic mulch 2-4" past the drip line. The mulch does not have to be acidic as acidic mulch will not help that much. I use hardwood mulch or hay or organic compost in some years. Tried pine needles too but those were a slight pain so I went back to the other stuff. No rocks as mulch ever.Use either garden sulfur, aluminum sulfate or greensand to acidify the soil. Or use liquid iron-chelated compounds sold at most plant nurseries. The liquids correct iron chlorosis faster than solids but they do not last as long.
Then I use either a moisture meter or the finger method to determine if I need to water them. I give mine 1 gallon of water in the Spring (per plant per watering) and increase that to 1.5 gallons in mid-May. I go down back to 1 gallon when temperatures moderate in September. When we hit the daily 100s or so, I may water using the hose at certain times too. Most of mine have drip irrigation but a few get water from the regular sprinkler. The drip does not do a perfect job though when temps are regularly in the 100s so I hand water sometimes when it is supposed to go "off".
Wilting episodes indicate that the plant is loosing moisture thru the leaves much faster than it can absorb water thru the roots. So blooms and-or leaves wilt. These episodes are common on the first year, when the shrubs have a tiny root system that cut to fit into the 1 or 3 gallon pots. After mid-May, I check these guys in the mornings. A hydrangea should fix the wilting episode on its own provided that its soil has enough water. If it shows up wilted during my morning inspection then I hand water them. I always water early in the morning and only the soil -never the leaves-. Water from the root ball outwards. The only exception to those suggestions: if I see a wilting episode that seems extreme, I immediately water and maybe check for things like the sprinkler system was not turned on, etc. In future years, as the plants' root system gets larger and the plants become established, wilting episodes will diminish but happen in very hot, very dry or windy conditions so consider if you want to water the day before the weather service says it will be hot or very windy.
Observations continued: The blooms in the picture look old/spent or suffering from heat stress. Hard to tell with some Blushing Bride blooms as they are not exactly white. But down here, blooms should open quite early, last several weeks/month-ish and by now, they should start color changing, adding greens, pinks, sandy colors and then browns. If purchased this year, they may have been forced to bloom early so it may be ok for them to turn brown early. But if the color progression skips all or most of the greens/pinks and goes directly to pinnk then the plant decided to zap them. Either due to heat stress or lack of water or lack of enough water. I did not see dried out stems (with no leaves), which is good as it means they are not getting periods of dry soil, then they get water but then the soil dries again and so forth. Uniformly moist soil -as best as you can- is what they like in their natural tropics.
A colored or white bloom that is under stress may eventually get zapped/killed if it regularly does not get water... or enough water. If not getting enough water on one day, they can wilt. Mophead blooms may end looking like they weigh a ton and be pointing down almost. If I cannot perk them up with water, I may deadhead: cut the petiole string that connects the bloom to the stem. Do not cut the end of the stems though; they will produce invisible flower buds for Spring in mid July or so.
Hydrangea flower buds and flower blooms are the first things to get zapped by the shrub when there is not enough soil moisture or when it is too hot. Normally, a bloom goes thru a plethora of color changes or splotches that end in brown. For example, the bloom starts pink then gets green spots and-or pink spots and finally ends brown. If it is too hot or they cannot get water or they cannot get water fast enough, the plant eventually shuts them down and a white bloom can go from white to brown.
Good news... while the picture was not clear enough, I did not see browning of blooms. A little pink in a few white blooms. And on the upper left hand corner, those old blooms started the color change to green.
Transplanting: So, based on those observations and assuming watering is not an issue and wilting is not an issue, you could try keeping them where they are, but add some artificial shade and move them when they go dormant in the December. You can put outside chairs on top of them to provide extra shade... or use umbrellas, or just about anything that you can think of. Some stores (Northaven Gardens; exit Forest Lane on US75) sell shade cloth. You can also use that; I use something similar in some areas of the garden. I try to plant them in the east/north side of trees (Live Oaks, Crape Myrtles, etc) or other things (the house, etc).
Here is the "but" section..... If the plants become distressed, consider instead pulling them out, putting them in pots/containers, keeping them there until December and planting them at that time. While waiting for December, review where else in the garden to place them. Now is not a good time to be planting/transplanting hydrangeas, camellias or azaleas. The transplant shock and our summer conditions are a pain to them and on us as we end up having to check them often and watering them often. But temporarily potting them is ok.
Sorry, this is way longer than I intended. The dogs woke me up to go outside so I guess I better go back to sleep! Ha. Does this help? Hope I did not ramble on for too long.
Luis
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Details for monitoring health of hydrangeas
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