The Effect of Five Pre-Emergence Herbicides on Emergence And Establishment of Four Native Wildflowers

Abstract

Careful selection of pre-emergence herbicide for control of weeds may improve establishment of native wildflowers grown for seed production. In a 28-d greenhouse herbicide injury experiment, 4 emerging wildflower species were established on soil treated with one of 6 pre-emergence herbicide treatments. No wildflower seedlings survived the atrazine treatment and few survived the sulfentrazone treatment. Of the 5 herbicides tested, DCPA applied at 1100 g active ingredient (ai) per ha (8 lb ai/ac) and trifluralin applied at 184 g ai/ha (2 pt ai/ac) caused the least reduction in wildflower seedling density, height, and shoot dry mass of all species. The densities, however, of <i>Dalea candida</i> Michx. ex Willd. (Fabaceae), <i>Gaillardia aristata</i> Pursh (Asteraceae), and <i>Ratibida columnifera</i> (Nutt.) Woot. &amp; Standl. (Asteraceae) were each reduced in 1 of the 2 experimental runs, whereas the height of <i>D. candida</i> and <i>G. aristata</i> and the shoot dry mass of <i>R. columnifera</i> seedlings were reduced by trifluralin. <i>Liatris punctata</i> Hook. (Asteraceae) densities were reduced only by atrazine and sulfentrazone.