Diggin' in: Water trees, shrubs in drought, but let lawn go dormant

August 12, 2010 By Kathy Van Mullekom, Daily Press (Newport News, Va.)

Intense heat and less than half of normal rainfall in many areas has left landscapes dry this summer.

Two Cornell experts provide advice: Water trees and shrubs, but not the lawn.

"In hot dry years like this, just let the lawn go dormant," says Frank Rossi, Cornell professor of horticulture.

"Think of your lawn like a hibernating bear. Many lawns will turn completely brown. But most of the lawn grasses will survive four to six weeks without significant rainfall. In most cases, they'll green up again in late summer or early fall, when the rain returns and the temperatures moderate.

"Overwatering during does far more damage to a lawn than drought. Watering - particularly frequent light watering - encourages lawn diseases and weeds. The cool-season lawn grasses commonly grown in the Northeast naturally slow down as temperatures rise and soil moisture decreases, even in normal summers."

But, don't give up on trees and shrubs that shed their leaves, according to Nina Bassuk, also a Cornell professor of horticulture.

"Go ahead and water them," she says.

"It's better late than never. If they're still alive, they'll grow new leaves. And after two weeks of photosynthesizing they'll have made up for the extra effort it took them to re-leaf.

"When it's really hot and dry, many trees and shrubs will shed their leaves - and some will just dry up. Drought is very stressful and can sometimes kill them outright.

"Newly planted and shrubs are particularly vulnerable because their root systems aren't fully developed. They have a harder time foraging for moisture. Depending on the species, site and planting practices, that might mean keeping 2- to 5-year-old plantings carefully watered during periods, hopefully preventing drought-caused leaf damage or loss in the first place."

Explore further: Amazon rainforest grows best in dry season


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