In last week’s column, I discussed how climate and soil type should play a role in deciding whether to invest in a lawn or landscape irrigation system. This week, we will look at a few other factors to consider in the big picture of irrigation.
Last fall, our business was working on a project with several moving components: Trees had to be removed, and a landscape had to be installed quickly so as not to disrupt business hours and traffic. This meant that coordinating delivery of supplies from multiple suppliers, planting dates, late-fall weather issues—all of these factors had to be properly aligned or the project would fail. At the proverbial last minute, another layer was added: the planting plan and schedule had to be coordinated with the planning and availability of the irrigation contractor.
On the one hand, since my business was responsible for the establishment of the plants, one might think that I would be grateful to work around an irrigation contractor’s schedule. After all, statistically speaking, receiving the proper amount of water in the first year or two is the chief predictor of survival for new plantings. On the other hand, I was very concerned: I know of no way to automate watering so that plants get sufficient, but not excess water. (If grass is overwatered, it seldom dies, but if many trees and shrubs are drowned, they will die). When I studied arboriculture, my Penn State professors told me of a tree transplant that incorporated dozens of water sensors into the root zone. The professors concluded that even such an investment of thousands of dollars was only a guess. They recommended instead that an annual plant like impatiens be placed near the tree. When the impatiens wilt, showing a need for water, you will know that the tree needs water—and the pot of impatiens costs less than $10. So when it comes to trees and shrubs, automatic irrigation is a gamble.
There is another irrigation factor to consider: What is the point of watering plants anyway? Think of a golf course in the desert. In a desert, lush, green fairways are completely artificial. From a water perspective, the best way to choose plants is to look at the type of plants that already thrive in the existing climate and soil type. Landscape irrigation is fundamentally artificial and therefore unsustainable.
In sustainability terms, compare installation costs, repair costs and seasonal maintenance costs—to prevent freeze damage, each fall, all lines must be “blown out” using compressed air. Compare these costs to the cost of pulling out a hose two or three times a year. While an irrigation system seems like a fight against nature, a hose, timer and sprinkler (as little as $100) are merely protecting your landscape investment from the extremes of nature’s cycles.
Reach me at firstname.lastname@example.org.
Joshua Arp is an ISA-certified municipal specialist, Clarks Summit’s municipal arborist and an operator of an organic lawn and landscape maintenance business.