Overwatering a Hydrangea can also stunt its growth, slow down its production of blooms, and eventually lead to its death.
Most common hydrangeas prefer a partial sun location - ideally receiving sun in the morning hours and shade in the afternoon. The reblooming Endless Summer® Hydrangea series prefers part shade.
Water your hydrangeas in the morning before the heat of the sun is strong enough to quickly evaporate soil moisture. Try to avoid watering at night, which can encourage mold and mildew as the moisture sits through the cool night. Water your hydrangeas through the growing season as well as in late fall.
Hydrangeas do best in moist, well-drained soil and dappled shade – not too sunny and not too shady. Avoid south-facing positions, especially if the soil is very dry. For a very shaded spot, such as a north-facing wall, grow the climbing hydrangea Hydrangea anomala subsp.
Most hydrangeas prefer partial sun with full sun in the morning, followed by some afternoon shade. This is especially true for the Bigleaf hydrangea (H. macrophylla). Some varieties are more tolerant of full sun. Most hydrangeas will thrive in fertile, well-draining soils that receive plenty of moisture.
Keep good air space between the plants; don't crowd them together or against other plants. Don't give bigleaf hydrangeas too much love; if they're too comfortable (water, fertilizer, etc.), they may devote all their foliage to leaves instead of blooms.
Too much sun exposure can cause your hydrangea shrubs to burn on its leaves and blooms. Also, be sure to put your fingers in the soil to see if it needs watering. We do recommend a soak versus light watering each day, but you should be sure that the soil is always moist – not wet – by sticking your fingers in the dirt.
Slowly water your hydrangea, giving it more water than you normally would. The water helps move the fertilizer through the soil and away from the root system of your plants. Note that this method only works on water-soluble fertilizers and not on many granular organic fertilizers.
Some gardeners report success in turning their hydrangeas blue by applying coffee grounds to the soil. The coffee grounds make the soil more acidic, allowing the hydrangea to more easily absorb aluminum. In addition, fruit peels, lawn clippings, peat moss and pine needles, are thought to have a similar effect.
The best place to plant hydrangeas is in a sheltered location with sunny mornings and shady afternoons. You often find this on the north or south side of your home. Avoid planting directly underneath trees, which can lead to competition for water and nutrients.
But hydrangeas are among the few plants that can draw moisture in through their florets, so it's possible to perk up wilted blooms by completely submerging them in water and letting them sit for a few hours to rehydrate.
Hydrangeas should be planted in moist, rich soil. In soil that drains quickly, such as sandy soil, wilting occurs much faster than in soil rich in organic matter with better water-holding ability. Shallow watering can also cause wilt.
Hydrangeas Are Great Container Plants
Potted hydrangeas are great alternatives if you only have areas where they are unlikely to grow well in the garden due to extreme cold or heat. Hydrangeas generally grow in USDA Zones 3-9, but in either extreme, they are unlikely to do very well. That's where containers come in.
Panicle hydrangeas can handle hot sun
While they are drought tolerant and stand up to heat, I still like to provide shade during the hottest part of the day. And just because they are drought tolerant doesn't mean you should let them wilt. As with all hydrangeas, plants will thrive with regular irrigation.
The basic rule to tell if a hydrangea needs to be watered is by looking at the leaves. If the leaves are drooping, the plant more than likely needs to be watered.
If you've overwatered your hydrangeas, you can revive them by removing dead roots and replanting them. Afterward, be sure to check the soil to ensure you only water your plant when it's required. And keep an eye on the growing conditions to determine what it needs.
Signs of Overwatering
When a plant is first becoming overwatered, leaves turn yellow. If soil doesn't have a chance to dry out before you water again, leaves start to wilt. When overwatering is the problem, wilted leaves are soft and limp. (If too little water is the issue, wilted leaves are dry and crispy.)
It's best to start adding coffee grounds to the soil months before the blooming season begins, ideally in the late fall. You can repeat the process with your typical fertilizing schedule. With a little caffeine and a lot of patience, your hydrangeas should reward your efforts come spring with the boldest blue globes.
You can use vinegar to lower the pH of your soil, but be aware that in order to achieve blue blooms, you will need both an acidic environment and aluminum ions. The acidic environment will also need to be a sustained over a period of time, which could be hard if rainwater is washing the vinegar away.
By altering the soil pH with vinegar, you can actually turn your pink-flowering hydrangeas blue! For this trick, simply dilute your vinegar in water before pouring it around the base of your hydrangeas, and within just a few weeks you could have fresh and bountiful blue blooms.