Released June 9, 2009
COLUMBIA, Mo. – Landscape plants have flourished over an ideal spring. Azaleas and hydrangeas have never looked better, but many of the lush leaves that developed during the mild weather will scorch, turn brown or even fall off when the summer heat returns, said a University of Missouri Extension horticulturist.
People should take care not to make the problem worse by overwatering, said Chris Starbuck. “We tend to water plants a lot when we see wilting or scorching, but overwatering will drown plants in poorly draining soil,” he said.
In some cases, a plant that loses all of its leaves to scorch and drought stress is more likely to survive than one with roots drowning in saturated soil, he said. “The important thing is that the soil should be kept moist, but not soggy.”
Check soil moisture by digging six inches with a trowel. If the soil is soggy, do not water, except perhaps to mist the top to provide a few minutes of relief from high leaf temperature during afternoons.
Two or three gallons applied twice a week will work better than 10 gallons every week or so, Starbuck said.
Dripping the water into the ground is better than applying it all at once. A leaky five-gallon bucket placed next to the plants can help them through the transition to hot weather, he said.
For more information, see these MU Extension publications:
“Irrigating Trees and Shrubs During Summer Drought,” http://extension.missouri.edu/publications/DisplayPub.aspx?P=G6879
“Leaf Scorch of Ornamental Trees and Shrubs,” http://extension.missouri.edu/publications/DisplayPub.aspx?P=G6881
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http://extension.missouri.edu/news/DisplayStory.aspx?N=443
Source: Christopher J. Starbuck, 573-882-9630
Editor: Robert E. Thomas, 573-882-2480, thomasr@missouri.edu
