Watering Strategies to Save Trees |
By Charles Fenyvesi
In this drought emergency, we should think of our trees first, the elders of our gardens. Or, to put it in raw money terms, they represent our prime investment. Removing just one and replacing it runs into hundreds, even thousands, of dollars.
In this third consecutive year of drought, many trees are highly stressed, their leaves losing their vital color or curling into cigars to conserve moisture. Some of them may be already too far gone.
We should try to save our trees while we still can.
But there is a correct and incorrect way to water them. Sprinkling--now illegal in Maryland--often leads to too shallow a watering. This promotes surface roots that simply dry out quicker than deep growing ones. A hose left to trickle will only reach a part of the root zone, unless it is moved, and is also illegal under Gov. Parris Glendening's order.
Water should be applied every three feet within the tree's root zone, which generally extends out a few feet beyond the drip line. This can be done quite effectively by buckets or handwatering by hose, allowed under the restrictions.
Ironically, the zealous gardener may kill trees (and shrubs) by overwatering them, especially on flat sites with compacted, clay soil. The water drowns the tree by squeezing out the oxygen from the breathing spaces in between soil particles. A mature tree needs at least 5 gallons per week. A plastic spackle bucket with holes punched for seepage works well.
In our metropolitan area, the drought emergency arrived early in the pleasantly green, tree-lined city of Poolesville, which relies on a limited number of fairly shallow wells. Already in July, residents were told not to use their hoses. Fines can go up to $200 for repeat offenders. The state's ban is backed up with maximum fines of $1,000.
"But people honor the restrictions," says Terrie Daniels who runs a popular health and fitness club in downtown Poolesville and lives in nearby Dickerson. "Nobody I know complains. I don't see people rushing to use my showers, either. My customers talk about reusing their dishwater for their plants. But the lawns are all brown. You go around Poolesville without seeing a single green lawn."
Some area residents not only haul buckets of gray water outside but rig up their washing machines with a garden hose, with the help of plumber's clamps or duct tape, to recycle the water for their gardens.
Nevertheless, Alberto Goetzl is afraid that each Poolesville household will lose at least one tree. His small leaf maple, which has not been doing well for years and has a trunk that is only three inches in diameter, is "mostly gone," he says, and across the street another maple, in fairly good health when the summer started, is no better off. He says that even mature lindens, the tough street tree in the neighborhood, are half-defoliated, looking stressed. "They may die by the end of the season," he says. "And trees already stressed will die."
At this late stage, he feels there is not much to do. Wells could run dry and restrictions get far worse before summer ends. Goetzl, a forester by profession, takes his impending losses philosophically. He says that now some 25 percent of the national forests are stricken by drought and the diseases and pests that take advantage of parched trees.
But even when it comes to trees, we should have some priorities. Certain tree species are more in need of water than others--dogwoods, birches, maples, and magnolias, for example. We could carry out our gray water in buckets and then pour the precious liquid into a leaky bucket moved about the root zone.
Older trees, particularly oaks with their deeper and more extensive roots, can take more drought than saplings with immature roots. But they too could be favored with a few gallons of gray water a week.
Among shrubs, we should watch for rhododendrons, azaleas, witch hazels, stewartias, viburnums, smoke trees and other favorites close to our hearts.
But let annuals die, which they will do this year ahead of schedule, because of the heat and the drought.
Above all, do not worry about the lawn. Sprinkling it will not help, and the amount of water needed to keep it green is too wasteful for a good citizen. Let the turf grass wither away. The odds are better than even that it is dormant, not dead. Like trees, lawns have long roots, and they may surprise you by returning to life next spring.
© 1999 The Washington Post Company