Replanting Lawn Under Trees? Think Again

Manhattan, Kansas (August 18, 2011)--Tall fescue is the best shade grass for Kansas, but that’s not saying much.

“Mostly, tall fescue is best because the state’s other recommended turfs can’t handle any shade. Tall fescue can handle some. It won’t survive over the long term, though, under a large tree that produces deep shade,” said Ward Upham, K-State Research and Extension horticulturist.

Tall fescue can raise false hopes, Upham warned. Homeowners plant it under trees in September. The turf sprouts and grows well though fall. It greens up again in early spring.

“Growing conditions tend to be cooler and moister then, and tall fescue is a cool-season turf. Besides, there’s less leaf cover,” he explained.

But, then comes summer. Hot, dry weather stresses cool-season turfs. In the extremes of 2011, for example, even well-watered lawns retreated into dormancy, Upham said.

“Shady areas are cooler. However, as sunlight filters through tree leaves, most of the ‘good’ light – the rays that drive photosynthesis – gets stripped out. Turf struggles to produce enough food for survival and growth,” he said.

When this poor diet combines with heat and drought, tall fescue simply can’t survive.

“For those who insist on trying to grow grass in shade, I advise going with a much lighter seeding rate -- 3 to 4 pounds of fescue seed per 1,000 square feet or about half what’s recommended,” Upham said. “With less competition, the turf will be thinner, healthier and likely to live longer.”

Even that won’t work in deep shade, though. In that case, he said, homeowners have three choices:

• If it won’t destroy trees’ shape, prune up their lower branches so more early and late sunlight reaches the turf.

• Plant a groundcover that is well-adapted to shady sites – e.g., periwinkle or English ivy.

• Mulch under the tree.

Contact:

Elaine Edwards
elainee@ksu.edu