We Hate To Tell You This, But You're Watering Your Hydrangeas Wrong

Irrigation tips and tricks for mopheads, oakleafs, and more.

watering hydrangeas
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The hydrangea can be a finicky flower, and determining what's wrong with your plant can be half the battle. From spotted leaves to powdery mildew, the issues that can arise from either insufficient or over-watering are many. But, even if you're giving your plants the perfect amount of water, the technique that you use to water them matters too. According to David Doggett, president of the Alabama Hydrangea Society and Advanced Master Gardener with certification in hydrangeas, hydrangeas are more vulnerable to water loss than other flowering shrubs and bushes because of their large leaves. "Additionally, hydrangeas' large flowerheads can hold moisture throughout the day, making them more susceptible to rot and fungal infections than other flowers."

It turns out, big leaves and even bigger flowers can turn into big problems if you're not up to date on your hydrangea watering know how. The good news is that many newer varieties are bred to resist disease and fungal issues that are oftentimes brought on by improper irrigation. "We trial hundreds of hydrangeas at all four of our nurseries, not only searching for unique qualities and beautiful blooms, but also paying extra close attention to their ability to withstand disease," says Georgia Clay, New Plants Manager at Monrovia. If you're adding hydrangeas to your landscape, selecting a disease-resistant variety can help avoid these issues but, if you're working with hydrangeas that don't have those benefits, there are certainly things you can do to help your mopheads, lacecaps, and more enjoy their waterings without any ill side effects.

The Right Way To Water Hydrangeas

If you water your hydrangeas with the hose nozzle raining down over those gorgeous blooms, it's time to change your technique. According to Karen Mitchell, Jefferson County Master Gardener, irrigating below the leaves and flowers at the base of the plant is best practice to avoid fungal-related issues and ensure the water goes directly to the root system. "This can be done with soaker hoses or low-pressure tubing with attached emitters," she says.

How much supplemental water you'll need to provide will be dependent on a number of factors, the most notable being the hydrangea variety, amount of sun exposure, and the time of year, though you can count on watering newly planted hydrangeas frequently to ensure they succeed in their new environment, advises Doggett. For more established hydrangeas, Clay suggests watering when the first inch of soil feels dry to the touch. "Every garden is different, so if the top inch of soil is dry, it's time to water," she adds.

What Time of Day To Water Hydrangeas

If watering at twilight is part of your routine or grabbing the hose around mid-afternoon is what you think is best for staving off the worst of the summer heat, you might want to consider making a switch to the early morning hours. "Morning irrigation of any type hydrates the plant to face the day," says Mitchell. If you don't follow our above advice and continue watering your hydrangeas overhead (tsk, tsk), watering in the early morning will also allow the leaves to dry before the heat of the day. Just be sure to avoid watering when the day's heat peaks. According to Doggett, "Water droplets on leaves can act as magnifying glasses, reflecting sunlight and potentially burning leaves."

Common Signs of Irrigation-Related Issues

Uh oh. So, it turns out you've been watering your hydrangeas wrong—whether too much, not enough, the wrong time of day, or (gasp) overhead. These are the issues to look out for, according to the experts.

Dry, Crisping Leaves

"Dry, crispy browning on the outer edges of the hydrangea leaf or flowers is another sign of water stress," says Kip McConnell, plant expert with Southern Living Plant Collection. "With prolonged water loss, your plant could lose flowerheads and leaves, jeopardizing the long-term health and survival of the plant."

Yellowing, Browning, or Spotted Leaves

"Plants with yellowing or brown leaves may have too much water," says Clay. "Be sure the plant, especially if it is in a container, is not in standing water." Doggett also points out that fungal issues caused by overwatering and under-watering could both result in browning tips on the leaves of the plant. But, rather than crisp-feeling edges, browning leaves that are the result of a fungal infection will be rotting and soft.

Wilting

Don't assume that your plant's wilting leaves are a result of under watering. Instead, give it time in order to properly diagnose the cause. "Hydrangeas can look stressed in extreme heat but will perk up when temperatures drop," says Clay. "If the plant is looking a bit sad even with cooler temperatures, it likely needs water."

How To Resolve Hydrangea Irrigation-Related Issues

If you find your hydrangea succumbs to fungal issues—whether due to irrigation, heat, or humidity—all hope isn't lost. Clay suggests using a fungicide to help remedy the issue, but also be sure to collect any infected leaves that have fallen and discard them in the garbage. Don't even think about adding them to the compost pile. "While the fungal infection is active, scale back your watering schedule without under-watering the plant," advises Doggett. "One place to start is being mindful of rain and summer storms. Allow those to serve as a natural pause in your watering schedule." Thinning out thicker foliage near the hydrangea can also help air circulation and thus reduce the potential for fungal issues.

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