Hello, Nur. Looks like leaves from a mophead, lacecap or a mountain hydrangea. All of these guys have large leaves from which moisture can escape. When newly purchased, they also have a limited root system (the roots have to fit in the pot) to absorb moisture thru. As a result, windy and/or hot days can result in wilting episodes. As the root system grows larger, the plant becomes established and can handle these problems (1-3 years at most) but, for now, you may want to give them some TLC. Hydrangeas bought at florists and grocery stores are coddled in greenhouse conditions that may even make them more sensitive to being outside on Year 1, causing what is called transplant shock. Note; some of these florist hydrangeas have issues in cold zones (6 or less).
If there are wind advisories, consider watering the night before. Water the plant from the base outwards and never the leaves. You can start by watering from 1/2 to 1 gallon of water per each watering (add 50% more water if in sandy soils). Consider using the finger method early in the mornings for 2-3 weeks: insert a finger into the soil to a depth of 4" to see if it feels wet, moist or dry. Water if the soil feels dry or almost dry. Each time that you water, make a note in a wall calendar. After 2-3 weeks then see how often you had to water, on average. If you had to water every 3 days for example, then set the sprinkler or drip irrigation to provide 1/2 to 1 gallon of water every 3 days. If temps change 10+ degrees and stay there, consider using the finger method again to see if you need to tweak things. I typically have to increase waterings or the amount of water per watering in May (when temps head to the 90s here) and again in late June or July (when temps head past the 100s). Then in September, I have to dial things back to Spring levels. Regularly increase the amt of water as the shrubs get larger and you notice you are watering "too" often. You should be watering deeply but with a pruned root system, now is not the time to do that. Once the hydrangeas go dormant in Fall or Winter, I dial back waterings to around every week or every two weeks, depending on how much rain I get. While leafed out, if you notice that the edges of the leaves are browning out inwards, they need more water. Aim to provide even soil moisture (no periods of dry soil, moist soil, dry soil again, etc.).
Wilting is a defense mechanism by which leaves bend and less of the sun hits the leaves and so they lose slightly less moisture. If the hydrangeas have enough soil moisture, they should recover on their own at night or by the next morning. In the future, if you notice a really bad wilting episode, immediately water from the base outwards. Otherwise, first test the soil with a finger and then water if necessary (the soil feels dry or almost dry).
The bloom may self correct if you maintain moisture as evenly as possible but it is hard to guess. Blooms and flower buds are the first things to go when there are issues with these shrubs. The colored blooms normally go thru a series of color changes thru the year. Yours start pink, may add some greens and other shades of pinks and finally end brown. If your soil is acidic though, they bloom colors in future years will reflect that by turning different shades of pink, purple or blue. After a few years of root growth, the colors should settle down and not change too much.
I noticed a lack of mulch on the picture so I would recommend year around mulch. Maintain 2-4" of organic mulch at all times. You can apply it up to the drip line or some distance past that if it is windy in that location regularly. It helps the roots feel warmer when it is winter and reduces evaporation which in turn means you water less often.
In case you are wondering, the brownish "dots" on the stems shown in your picture are common on some hydrangeas. They are not a reason to worry.
Hydrangeas do not need much fertilizers. Compared to things like roses, I mean. I have forgotten to feed them in some years and it has not made a difference. The only exception is in sandy soils. Assuming these are hydrangeas purchased from a plant nursery, they will be fine if you start with 1/2 cup to 1 cup of either organic compost, composted manure, cottonseed meal, etc. You can also use a chemical fertilizer labeled as a slow-release, general purpose fertilizer like Osmocote's brand whose NPK Ratio is 10-10-10 (or close to those numbers). Apply this in Spring and that should be it. In southern gardens close to the Gulf of Mexico or in Florida, the shrubs stay green longer and may do fine with a second application in Fall but I look for fertilizers with less nitrogen in their NPK Ratio. If your soil is alkaline, you may want to amend the soil to prevent the leaves from turning light green or yellowish (except for the veins which remain dark green); amend the soil per label directions using either greensand, garden sulfur, aluminum sulfate (but keep away from azaleas and rhododendrons) or iron-chelated liquid compounds (available at plant nurseries). Note: if your hydrangeas already had those round fertilizer pellets then there is no need to fertilize this Spring.
The sun sensitive leaves of these hydrangeas should get shade by 11am-12pm in the summer. Aim for morning sun and afternoon/evening shade. Just a few hours of morning sun is ok; so are dappled sun and bright indirect shade conditions. If they are getting too much sun, the leaves in direct contact with the sun may turn yellow/white-ish. To protect them from their first summer sun, I sometimes have used umbrellas or outside chairs to provide additional shade in their first summer.
These three hydrangea types develop invisible flower buds at the ends of the stems anywhere from July-September (closer to July in the South and closer to September in the North). The blooms then open in the Spring and look like a tiny head of broccoli. To bloom reliably in early Spring, some people winter protect them by putting a chicken wire cage around them and filling it with dried out leaves, mulch or composted hay. Put some cardboard/rocks to prevent the leaves from flying off and add more filler in mid-winter if there has been settling of leaves. Re-bloomer hydrangeas will also bloom again on new growth in the late Summer or Fall time frames (although in cold zones that can be a problem if your growing season is short).
There is no need to prune hydrangeas normally. This time of the year though, when they awake from dormancy, you can cut down stems that have not leafed by mid-to-late May. Should there be a time you need to prune, do this before the invisible flower buds develop in July-September. If the spent blooms are not to your liking, you can cut the string that connects the bloom to the stem.
There is no such thing as an inside hydrangea. Except when people sometimes bring them into garages in winter when they are dormant, they do not perform well inside on a long term basis.
Does this help & answer your questions? Luis
Springcolor, love your doggie picture. Reminds me of my Brandy Girl. RIP. She was a good baby.