Ecological Restoration Specialists

King County cottonwood study

King County recently published a 2-year study evaluating the effects of spraying grass versus irrigating on cottonwood live stake survival in a sunny, sandy loam site. The thought-provoking study found no benefit from applying one gallon of water per plant 5-6 times per season, but the grass-spray treatment had a positive effect. On this site, grass control effectively increased the cottonwoods’ access to water, but the irrigation did not. You can see the study results at https://soundnativeplants.com/…/King-County-Monitoring-Memo…