OUR COASTAL PLAINS
ONLY TIME WILL TELL THE EFFECTS of FLOODS ON REGIONAL VEGETATION
BY KATHLEEN PHILLIPS
Unlike people and animals, plants can’t evacuate when threatening weather approaches, and long tenures in floodwaters can take a toll. As water recedes, landscapes — and the entire coastal plains — also will need to be watched for signs of stress.
“A little bit of rain is not too bad, but too much rain can be detrimental to the health of any plant,” says Stephen Brueggerhoff, Texas A&M AgriLife Extension Service horticulture agent in Brazoria County. “These were extraordinary circumstances, so at this point, it is really just a matter of waiting to see what the impact is.”
Brueggerhoff says soil saturation is key. “For perennial plants, what we really are concerned with are saturated soils that create conditions for root rot,” he says. “When the rain saturates the soils causing a collection of water, plants may be standing or submerged in water.”
Once saturated, there are not many options to help perennial plants, he says, except to watch for signs of stress. Stress reveals itself in plants through discoloration, often as yellowing or purplish leaves.
“The roots of all plants need oxygen through the soil,” Brueggerhoff explains. “Once the soils get saturated, that creates an anaerobic environment where the roots are not getting proper oxygenation within the soils.”
SHRUBS & TREES
Woody species such as shrubs and trees take longer to show stress, he notes.
“They often don’t tell us too quickly what is going on with them, as far as decline. Sometimes we will not see a tree or shrub responding to those kinds of environmental conditions for six months to a year,” Brueggerhoff says.
He described an ash tree that stood in four feet of water near his home for two days.
“The water receded quickly, so two days of saturation probably is not going to hurt that tree,” he says. “But if we have plants that are under saturation for up to a week, for some plants it can cause a decline in the long run. Sometimes those kinds of conditions can be an entry point for other pathogens to grow. And things of that nature can cause plants to decline in the long run.
“At this point, it is just a matter of waiting to see how our plants respond.”