Welcome to NGA. This is typical of hydrangea blooms. The original bloom color lasts about 1 to 2 months. Once the blooms start to age, the blooms then begin to color change multiple times until the blooms end brown. The exact color progression of the blooms varies by cultivar and by the type of hydrangea. Just as an example, the blooms may start a shade of purple when the dormant summer 2023 flower buds open in spring 2024. Then the purple color begins to fade. Then the sepals add some shades of green. Then the sepals add some shades of dark pink/burgundy. Then the blooms turn brown. Each color progression lasts for a variable number of weeks, sometimes influenced by more or by less sun exposure.
The shrubs look healthy. They prefer a morning summer sun exposure until 11am or earlier. Sometimes though, if summers are mild, the shrubs can tolerate a few hours of early afternoon summer sun. In year one, re-confirm during the summer months that the shrubs are still receiving morning sun as the sun now strikes at an angle but strikes from overhead in the summer.
They are thirsty plants that prefer soil that is evenly moist, never dry but never wet. Ensure that the soil is consistently and sufficiently watered. To water consistently, test the soil at a depth of 4 inches under the canopy often and water the soil -never the leaves- as soon as it is dry at that depth, the typical depth of new hydrangea plantings. Never water if the soil is already soggy prior to irrigation time. To water sufficiently, periodically wait for the water to percolate and then test the soil at a depth of 8 inches to see if the soil is moist (if dry, use more water; if soggy, use less water). Maintain 3 to 4 inches of organic mulch (no rock mulch) all months of the year.
Expect some leaf wilting during periods of high winds, soil with insufficient moisture, after disturbing the tiny shallow roots, or high temperatures. The leaves tend to lose leaf moisture faster than the roots absorb soil moisture when temperatures reach or typically exceed 85°F. For Corinth, that can occur from late May through September. Since last Sunday and Monday temperatures reached these levels, one or both plants may have exhibited leaf wilting. You could also observe blooms and leaf wilting as well when hotter. Wilting tends to self correct once the environmental conditions recede at night, provided the soil is kept evenly and sufficiently moist. If wilted in the morning, the amount of soil moisture was not sufficient to perk the leaves by themselves so water in the morning. In a severe wilting emergency, consider temporarily extricating the shrub(s) and dunking it in a pail full of winter in full but bright shade. After the soil stops throwing air bubbles (1-2 hours?), you can move the shrub back to its original planting location. You can also leave them in water until later at night if you need to.
Big Leaf Hydrangeas (h. macrophylla) like yours tend to break dormancy in stages. First, the shrubs begin to grow new stems in spring from the crown/base of stems. You can begin to water at spring watering levels at this time as soon as the soil is dry. Then the leafless live stem will leaf out, maybe a month or so later. If these leafless stems fail to leaf out by the end of May, you can assume they are dead and you can prune them down. Then the leaves of the leafless live stems unfurl for several weeks or a month. Finally, after the leaves are completely unfurled, the flower buds from last summer open and resemble tiny broccoli heads.
Fertilize after your city's average date of last frost around the 3rd-4th weeks of April. The last fertilizer application should be done 3 months before your average date of first frost around the 3rd-4th weeks of October (so stop by the 3rd-4th weeks of July). You can use any general purpose, slow release fertilizer with a NPK Ratio of 10-10-10; or you can use a cup or so of organic compost, composted manure, cottonseed meal. You can also use Holly-tone as a fertilizer but apply it at full strength in late April after all danger of frost has passed and then only a second time by the end of July at half strength.
Hydrangeas typically prefer soil that is either acidic or neutral. If your soil has an alkaline soil pH higher than 7.0 (consider getting a soil pH kit with numeric results) then you need to amend the soil regularly. You can use garden sulfur or aluminum sulfate to acidify the soil. Apply it per product directions as the formulation can vary. Re-apply per product directions so the soil does not slowly revert back to alkaline. These amendments are very slow acting so use the soil pH kit maybe once a month at most. Blooms are affected by the soil pH and nutrients like aluminum. A soil assay on the potting mix can help you get an idea what pH/nutrients the wholesaler used to produce these bloom colors. In time, new blooms may change their initial color to adjust to your garden soil's pH/nutrients instead.
Winter hardiness can vary from one variety to another. To ensure spring 2025 blooms and the survival of the summer 2024 dormant flower buds due to sustained wildly fluctuating temperatures that crash well below freezing, consider winter protecting from through your city's average date of first frost around the 3rd-4th weeks of October through your average date of last frost around the 3rd-4th weeks of April.
Because this species of hydrangea spends most of the year loaded with flower buds inside the ends of the stems, it is best sited where it can attain its estimated size at maturity and the never/rarely pruned.
Review the plant label for these shrubs to determine their estimated size (width and size) at maturity. Then determine if the planting locations are adequate with their estimated widths. Ensure you keep the equally shallow rooted grass away from the hydrangeas' shallow roots so they all do not compete for water and nutrients. Mulch can be used to help suppress weeds or you can use a metal barrier. If the estimated width is 3 feet for example, form a circle with a diameter of 3+ feet, centered on the crown/base of stems.
