Managing weeds during wildflower meadow establishment in the arid Intermountain West: efficacy of a grass-first strategy for sites with heavy annual weed pressure

Abstract

The creation of attractive, sustainable wildflower meadows in private and public green spaces is becoming increasingly popular. Establishment failure rate for new meadow plantings can be very high, primarily because of the initial annual weed pressure. We proposed a 3-step grass-first establishment protocol based on plant augmentative succession principles: 1) spring planting of grass component species; 2) application of standard turf-appropriate weed-control methods; and 3) early fall overseeding or outplanting of forbs into the established grasses. This grass-first meadow establishment protocol was successful, regardless of standard weed-control method employed (mowing; 2,4-D application; or application of a three-way pre-mix containing mecoprop, 2,-4-D, and dicamba [Ortho Weed B Gon]). Among the weed-control treatments, weed density during the establishment year did not affect ultimate meadow establishment success, as long as weeds were controlled sufficiently to allow grass and forb survival. Seeding resulted in a greater density of forbs and, ultimately, an overall more aesthetically pleasing mix of flowering plants and grasses as compared to outplanting. Among the grasses in the species mix, slender wheatgrass (Elymus trachycaulus (Link) Gould ex Shinners [Poaceae]) was dominant. Among the forb species, 5 Asteraceae species persisted over the period of the study and contributed good color to the meadow plantings. An augmented succession protocol based on grass-first establishment will be valuable where native meadow plantings are desired for urban habitat development and beautification.