This past week, I spent an afternoon with my son playing golf. Please understand that while we were playing golf, I am not a golfer. We played from 2 pm to 6 pm, and the hot sun and humidity were brutal.
I know I’m not going to fare well outside for those few hours. I also know our landscape plants not going to fare well in the hot, dry days that can stretch on for weeks.
We know our annual weather pattern. High temperatures and low rainfall are in store until sometime in late September when cooler fall weather arrives.
So we until cooler fall temperatures and rainfall, we can expect moisture stress on lawn and trees, and honestly everything else. We can overcome this stress with a couple of strategies. A great first step to reducing water stress under trees and in beds doesn’t involve water at all.
Just add mulch.
Adding and maintaining a three-inch layer of plant-derived mulch, such as native hardwood, will significantly reduce the amount of water required in the landscape. This is especially true when drip irrigation is placed underneath it. Mulch also helps prevent weeds and erosion, modifies the soil temperature, and serves as continuous supply of organic matter for the soil beneath. Mulch can easily be added to an existing landscape.
Secondly, drip irrigation is a tremendous practice for trees, shrubs, and other bedding plants. Drip (or micro) irrigation is typically at least 90 percent efficient compared to traditional sprinkler irrigation (50 to 70 percent) because it applies water only where it is needed and slowly enough to minimize runoff and evaporation loss. It also reduces salinity damage and disease on foliage by keeping the water and soil splash off the plants’ leaves. A wide variety of products and kits are available, as are many internet resources that offer guidance on installation.
Lawns with irrigation systems are often over watered or incorrectly watered. Turfgrass should be irrigated no more than twice a week except in cases of the coarsest sands.
For the grass alone, apply one inch of water once a week when we get dry. Modern irrigation systems include a soil moisture sensor. This is a wise addition so that we don’t overwater because of natural rainfall.
Now one inch per week would also be enough for your trees but if you will put out two inches every third or fourth watering, it will encourage deeper root on your trees.
Regarding trees, I believe the oak to be the most temperamental with irrigation. The absolute minimum for oaks, during the growing season when it is not raining, is a single, two-inch application of water once a month. Again, this is only the minimum possible when turf is not used.
Optimally, oaks should receive two inches of water once every ten days throughout the summer in the absence of rain. If you have turf under your trees, apply one inch of water per week for the turf and then apply an extra inch every third watering to reach the deeper roots of the trees.
These basic irrigation and mulching strategies will greatly help improve your landscape. As for my golf game, let’s just say that I’m in it to spend quality time with my son this summer.
