Flooded landscapes require care

Richard Bogren  |  8/16/2016 6:48:25 PM

(08/16/16) BATON ROUGE, La. – Root damage through drowning or root rot is the greatest danger to landscape plants caused by flooding. And even if a property didn’t have standing water, it likely has been saturated. And the longer the soil stays saturated, the more damage occurs.

Plant roots get the oxygen they need from air spaces in the soil, said LSU AgCenter horticulturist Dan Gill. When these spaces are filled with water, roots are deprived of the oxygen and may drown.

“Initially, the roots stop functioning properly,” Gill said. “When the bright sun comes out, it’s not unusual for plants to wilt because the roots quit absorbing water.”

If flood waters remain for several days, shrubs and herbaceous plants may be extensively damaged or killed.

“Carefully assess shrubs that may appear dead,” Gill said. Scrape the bark in several areas. Green tissue under the bark indicates the shrubs are still alive and may recover.

Don’t be too hasty in removing landscape plants. Some plants that appear dead may begin to send out new growth a few weeks after the water recedes, Gill said. But shrubs that show no green tissue below the bark are likely dead.

Flood waters carry silt and debris that may be deposited on lawns as well as low-growing plants, such as shrubs, ground covers, annuals and perennials. It’s important to remove the debris as soon as possible, using a rake to remove most of the larger material and then a hose to wash off the remainder.

Also remove all mulches to allow the soil to dry out more rapidly. Then replace them.

Even if fruit and vegetable plants are still alive, do not consume any fruits, vegetables or herbs that were or could have been touched by flood waters, Gill said. Remove and discard any produce.

You may, however, eat any fruit from trees, shrubs and vines in the future. And you may also generally eat the new growth of herbs and vegetables produced after the flood waters recede.

If a lawn is damaged or killed, a new lawn can be established or an existing lawn can be repaired using sod, plugs or seed.

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