Advice for gardeners on dealing with water-soaked plants

Gardening experts say standing water can wreak havoc on many plants, but most issues can be controlled with proper soil drainage.

With rain in over-abundance this week in Iowa, the best advice is to create drainage channels if an area of a lawn or garden is puddling with water, said Roger Strohbehn, Linn County Master Gardener.

Strohbehn said too much standing water can kill grass and other plants, although bluegrass seems to be more tolerant of wet soil.

Homeowners might have to hire a landscaper or elevate the area of the lawn with additional topsoil and replant with grass seed or sod to correct the problem after the water drains, he said.

Other rain-related issues include toadstools in lawns, powdery mildew on plants, anthracnose on trees and tomato blight on tomato plants.

“Anytime we get these damp, humid conditions, it's a prime time to get these funguses started,” Strohbehn said.

Most plants can survive, but Strohbehn advised watching the lower leaves of tomato plants for yellowing. Those leaves should be removed and discarded. Fungicides for tomato blight must be applied when symptoms are first noticed to be effective, he said.

Strohbehn noted that no chemicals are effective against toadstools or other fungus growing in lawns.

Most die off quickly with sun and heat, but parents of toddlers who might be tempted to eat the non-edible fungus can mow it or rake it off and discard, he said.

Strohbehn said anthracnose, a group of diseases caused by several fungi, doesn't usually kill trees, but can stress trees that are attacked for years.

Phlox and lilacs are especially susceptible to powdery mildew, but again, the disease doesn't usually kill the plants.

The best advice is to create better airflow by trimming the plants, he said.

Linn County Master Gardener, Deb Walser, said she plants water-loving plants in poor drainage areas.

Examples include white swamp oak, dogwoods and willows.

Walser said some people are concerned about their silver maples, an example of a tree that cannot tolerate excessive moisture.