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Excessive water can damage plants

Excessive rain-fall and soggy soils have caused problems not only for our vegetable gardens but in home landscapes, too. The roots of trees and shrubs are showing the effects of prolonged saturated soil conditions.

If plant roots are exposed to standing water for extended periods, roots often die from “anoxia,” a term which means oxygen starvation. Damage occurs to trees and shrubs in obviously wet areas in the home landscape and to those along city streets and other landscape areas where drainage is poor.

Damaged plants lack the ability to pick up water due to their compromised root systems. One of the first signs of damage from soggy soils is wilting. Affected trees and shrubs may also show symptoms of nitrogen deficiency (leaf yellowing). Cessation of growth, twig dieback and leaf drop are frequently observed.

After the soil drains, plants with severely damaged roots may subsequently suffer drought stress and eventually die. For many of these plants, the only functioning roots are near the soil surface. When dry weather follows a wet period, surface roots quickly dry out. Plants exposed to flooding may also become more susceptible a disease called phytophthora root rot.

Unfortunately, not much can be done to improve the health status of water damaged trees and shrubs. Practices such as shallow trenching and berms can improve surface drainage. Hold off on fertilization. Root drench fungicides probably won’t help either.

It has been a hard couple of years on our landscape plants. Let’s hope a more normal summer weather pattern will arrive.

Rebecca Bates is an MSU Extension-Lincoln County agent, and can be reached at 601-835-3460 or by e-mail at rebecca.bates@msstate.edu.