Coast Gardener
Flooded landscapes are compliments of Bertha
Coast Gardener Newspaper and Web Column - August 10, 2002
The recent heavy rains in some locations in south Mississippi have created soggy soils that certainly have caused problems in home landscapes. Isolated reports of limbs breaking and trees caving over from excessive rainfall have been recorded as well.
Flood damaged landscape plants initially suffer from decreased oxygen levels to the root system. Waterlogged soils do not allow roots to absorb adequate oxygen; therefore, many plants can suffer from a condition called anoxia. In areas where poor drainage is often observed, standing water for an extended period of time can cause this condition to occur.
Damaged roots cannot absorb water either. As a result, soggy soils can cause the plants to wilt. It is not uncommon for leaves of damaged trees and shrubs to turn yellow. The needed nitrogen cannot be absorbed through the root system. Some trees may stop growing and the ends of the limbs may die back as well. Leaves can even shed prematurely.
The most important thing to do following a flash flood is improve surface drainage. Soggy soils need to drain as fast as possible to minimize the damaging effects on plant roots. Digging a shallow ditch may help alleviate standing water; however, be careful not to further damage roots.
Aeration is also important. Make small holes within a plant's root zone by using a pitchfork or other gardening tool. Soil aerators are available for rent at rent-all dealerships and some garden centers.
It is best to avoid fertilizing your trees and shrubs until after the shock is over. It may be next spring before some plants recover depending on the severity of the localized flooding.
Isolated wind gusts may have caused damage to some trees including broken and torn limbs, wounds, split branches, and exposed roots. The care given to injured trees depends on the extent of the damage, age of the tree and the time needed for the surrounding soil to reach normal moisture levels.
Removing broken or torn limbs can be dangerous, and it may be necessary to hire a professional. To remove a heavy, large limb, make three cuts to avoid more damage to the bark and wood. Make the first cut on the underside of the limb about one foot from the trunk. Cut one-third through the limb. For the second cut, move two to six inches farther out the limb, and cut from the upper side of the limb until the branch is completely separated. The final cut is made almost flush with the trunk that is being pruned.
Do not apply tree paint or dressing to the exposed wood surfaces after limbs have been repaired or removed. Latest research shows that this causes more harm than good, since the wounded area stays wet and harbors fungi and bacteria.
Some uprooted trees may need to be removed depending on the severity and size of the tree. Others can be reset, but braces may be required. Some braces need to remain about two years. Cut and smooth irregular root breaks before resetting the tree. Water thoroughly after resetting and continue watering during dry periods.
Cover exposed roots to the same level as before the damage. A three-inch deep layer of mulch, such as pine straw, retards drying of exposed roots.
Trees are not the only parts of the landscape damaged by storms. Silting, which occurs when soil is dumped on flood land by water, can damage or kill smaller plants or turfgrass. If the silt is more than a couple inches deep, it should be removed. To reduce injury to plants, remove silt from the crowns, or centers, of plants. Wash silt from well-drained soil with a hose, and rake away dried mud from grassy areas. Small amounts of silt are not harmful and may be raked into the grass.
Emergency information packets are available at the Harrison County Extension Service office in Gulfport. Emergency preparedness information is also available online at http://msucares.com/disaster/. Planning ahead can keep you ahead of the storm.
These archived gardening columns were written by Chance McDavid, former Harrison County Extension Agent.