Gardeners are now dialed into the regimen of reading the newspaper articles, water statements and web page links providing information about current landscape water restrictions. Does your landscape like the water coming from your spigot? Make no mistake; water providers in Colorado follow strict standards to ensure safe drinking water. However, some water is better than other for landscape sprinkling.
Colorado is known as a headwaters state. The continental divide is the hydrologic divide where streams originate. Most surface water originates from snow-melt.
This describes water in underground aquifers. In eastern Colorado this includes the multi-state Ogallala and regional Denver aquifers. These waters include precipitation that percolates through the soil and stream recharge.
Recycled or reused water is sewage effluent treated in various processes of which usually includes salt. Recycled or reclaimed water is being used primarily on public properties such as parks and golf courses.
The Life of Water
Water begins its life as natural precipitation. As water continues its journey to you, it contacts soils and geologic formations. Flowing over this geology, water gradually picks up minerals and salts.
Less is more. The less water has in it the better it is for your lawn, shrubs and trees. The highest quality water is piped in from high mountain reservoirs. This water has the least exposure to decomposing rocks and soils. Water’s that travel long distances by streams stored in lakes or underground aquifers may pick up more minerals and salts along the way.
Salts interact with plants somewhat in the same way as salty foods do with people. Salt leaves us thirsty. In plants, salts inhibit roots’ ability to pick up soil moisture leaving the plant water deficient. Excess in specific minerals compete with others for plant uptake in the soil solution. Affected plants may become drought and nutrient deficient.
In the soil Sodium salts work to break apart individual particles. Soils may become very compacted. As soils compact, porosity is decreased impeding soil respiration and water percolation.
Lawns may seemingly need more and more water to stay green. Water puddles on the soil surface. Woody plant injury begins with leaf edges scorching and turns brown. Needles of evergreens become bleached. With continued salt exposure plant growth decreases and branches begin to die off.
What to do if you suspect injury from saline water
There are no one size fits all solutions. Have a qualified arborist look at your landscape. Symptoms of salt injury may be mimicked by other causations. Then, if needed, have your water and soil tested by a laboratory. Soil based treatments exist, however by design – slow acting.
In addition to treatments, some landscape plants are more tolerant of soil salts. Spruce, ponderosa pine, Austrian pine, red maple, silver maple and linden are sensitive to soil salts. Ash, honeylocust, many oaks and elms are tolerant.