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Water Saving Alternatives to Bluegrass |
By Jim Klett, professor, Colorado State University Department of Horticulture and Landscape Architecture
Non-turf groundcovers versus Kentucky bluegrass: Which uses less water?
It's a popular notion that groundcover plants use less water than Kentucky bluegrass. A research project conducted by Colorado State graduate student, David Staats and supervised by Cooperative Extension Landscape Plant specialist Jim Klett, provides some new insight on this subject. Staats undertook the project, with the knowledge that 90 percent of lawns in the Denver area are Kentucky bluegrass and, in residential areas, lawns and landscapes account for 50 percent of water used. While we assume that groundcover plants use less water, we have no definitive studies to prove it.
Staats compared Kentucky bluegrass "Challenger," with groundcovers snow-in-summer, creeping potentilla and goldmoss sedum. Irrigation treatments were based on 100 percent, 75 percent, 50 percent, 25 percent and 0 percent ET rates. Water was applied every third day and information measuring growth, visual quality and soil moisture was collected every nine days. Here are the findings:
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Kentucky bluegrass maintained good quality at irrigation rates as low as 50 percent. This indicates that many of us may be overwatering our lawns or that our lawns are suffering from poor micro-climate conditions, such as disease or poor soil preparation at the time of planting. |
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Snow-in-summer maintained good appearance at irrigation rates as low as 25 percent of ET rates. It might be a water-conserving alternative to Kentucky bluegrass, but its visual quality declines during seed formation, something homeowners may want to consider. |
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Creeping potentilla required irrigation rates between 50 percent and 75 percent of ET. Although it still can be considered a low-water user, it can't be recommended as a water-conserving alternative to Kentucky bluegrass. |
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Goldmoss Sedum was able to sustain good quality at 25 percent ET and could be considered as a water-conserving alternative to Kentucky bluegrass. |
Photos: Judy Sedbrook
