Field Evaluation of Preemergence Herbicides for Weed Control in Container Grown Woody Landscapes Plants.
by Sharon A. Duray, and Fred T. Davies, Jr.
Four preemergence herbicide combinations were evaluated for weed control and phytotoxicity on Silverberry (Flaeagnus pungens Thumb). Spanish bayonet (Yucca aloifolia L.) and Heavenly bamboo (Nandina domestica Thumb.), grown in 3.8 1 (1 gal) containers under commercial nursery conditions. Combinations of Root (oxyfluorfen : oryzalin) and Rout GL (oxyfluorfen : alachlor) were applied as granules at 1.12 : 0.56, 2.24 : 1.12 and 4.48 : 2.24 and 1.12 : 1.12, 2.24, and 4.48 : 4.48 kg ai/ha (1.0 : 05.2.0 : 1.0, and 4.0 : 2.0 and 1.0 : 1.0, 2.0 : 2.0 and 4.0 : 4.0 lb. ai/A), resp. Harness (acetochlor) was applied as foliar spray at 1.68, 3.36, and 6.68 kg ai/ha (1.5, 3.0, and 6.0 lb ai/A) and Zorial (norflurazon) was applied at 1.12, 2.24, and 4.48 kg ai/ha (1.0, 2.0, and 4.0 lb. ai/A) as a soil drench. Containers were overseeded with a weed mixture prior to herbicide application and six weeks later to induce extreme weed competition in containers, Harness, Rout GL, and Rout provided 90-100% control for up to 14 weeks after application at the highest rates evaluated. Zorial resulted in unsatisfactory weed control. None of the herbicides caused any phytotoxic effects on any of the plants tested.
J. Environ. Hort. 7(4): 140-142, December 1989.