Summer’s heat has settled in, and the afternoon sun can be brutal. Our trees, shrubs and grass often respond by wilting. But step away from the sprinkler! Some wilting does not call for water, and watering in the afternoon may do more harm than good.
Conservation
Drooping leaves sometimes act as a coping mechanism, helping plants to conserve water by minimizing the amount of leaf surface facing the sun’s direct rays. Less direct sunlight reduces evaporation and slows water-consuming photosynthesis.
Some plants, like hydrangeas, may wilt to protect themselves from the afternoon sun and then perk up by morning, no water required.
Disease
In rarer cases, drooping leaves may indicate a fungus or other disease. Fusarium wilt, bacterial wilt and Phytophthora can all cause plants to wilt, eventually killing them. Additional watering only encourages the disease to spread. Diseased plant material should be removed, including the soil around the roots, to avoid infecting future plants.
Dehydration
Of course, wilting can be a sign of drought stress. In non-woody plant material, water pressure within the cells helps keep the stems and leaves erect. When the plant gets too low on water, the stems and leaves droop or curl, indicating the need for water.
Many grasses may even show stress by curling their leaves or changing color. Some varieties turn a lighter green or even develop a blue cast when in need of water, although not all grasses react by wilting.
Wait to Water
When you see wilted grass, plants and trees in the midst of afternoon heat, your instinct may be to water them immediately, but they will be better off if you wait until morning. The plant may perk up on its own, so you’ll avoid the risk of overwatering. Also, watering in the afternoon wastes water, since as much as 25 percent is lost to evaporation. And finally, excess water left on leaves overnight invites disease.
Ideal Irrigation
Water in the morning before the dew dries. Water more deeply and less often to promote deeper roots, for more drought tolerant plants. Most trees, shrubs and grasses thrive with a half inch of water from rain or irrigation every three or four days, more often during extreme heat or drought. If you use automatic sprinklers, install a rain sensor to avoid overwatering.
If you have questions about caring for your lawn during the heat of summer, or if you’re looking for a more drought tolerant sod, contact our Certified Turfgrass Professionals at 770-832-8608 or info@NGTurf.com.
