Utilization of Weed Suppressive Ground Covers in Nursery and Christmas Tree Settings for Enhanced Weed Management and Soil Amelioration 2006
Project Leaders: L. Weston, R. Harmon , J. Condzella, Department of Horticulture, Cornell University, Ithaca NY
Cooperators: C. Albers, CCE Steuben County; Marcus Farms Nurseries, Arkport NY
Abstract: Nineteen cool season grass cultivars were selected for further field evaluation in 2006, based upon their potential to overwinter well in the Northeast and to tolerate stressful production site conditions. We were particularly interested in their winter hardiness, and ability to rapidly establish a dense stand and suppress annual and perennial weeds under minimal maintenance, simulating conditions encountered in low maintenance production sites. Grasses were seeded on September 10, 2005 at 4lbs/1000 sq ft on a well-drained Hudson silt loam soil in Ithaca NY, at the Bluegrass Lane Turf and Landscape Research Center. Plots were evaluated in April 2006 for winter hardiness and survival, and later in May, June and July 2006 for their ability to produce cover or above-ground biomass, and also to suppress the establishment of weeds. Plots received no fertilization and no irrigation after seeding, and minimal monthly mowing with a large commercial rotary mower. Grasses which performed exceptionally well in terms of weed suppression and biomass production included crested wheatgrass, creeping meadowgrass, no-mow fescue, Rebel Exceda tall fescue, Tar Hill II tall fescue, and Russian winter rye. Columbra and Intrigue chewings fescue and Palmer perennial ryegrass were also good performers. These cultivars generally produced greater than 80 to 90% stands of cover with minimal weed infestation by July 10, 2006 and continued to perform well into the fall of 2006. Grasses which performed poorly as evaluated by formation of less than 60% stands and supported large weed infestations included redtop, and Arizona fescue. Grasses will be further evaluated for their ability to withstand environmental stress and perform under low maintenance conditions both in Ithaca and Riverhead NY locations. In additional studies performed at Marcus Nurseries in Allegheny County, several groundcovers proved to be exceptional performers in nursery settings, 2 years after establishment. These groundcovers established and overwintered effectively, and were significantly weed suppressive. They also had no deleterious effects on growth of Frazier fir seedlings transplanted into killed groundcover strips. Best cover crop performers in nursery settings included Intrigue and Wilma fine fescue, and white clover/fine fescue mixtures. Palmer and Prelude perennial ryegrass provided poor weed suppression, despite good initial establishment. Fine fescues were generally most weed suppressive compared to all other groundcovers evaluated and required limited mowing for maintenance.