Native Plants Journal - Article

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 Dalea candida Michx. ex Willd. (Fabaceae), Gaillardia aristata Pursh (Asteraceae), and Ratibida columnifera (Nutt.) Woot. & Standl. (Asteraceae) were each reduced in 1 of the 2 experimental runs, whereas the height of D. candida and G. aristata and the shoot dry mass of R. columnifera seedlings were reduced by trifluralin. Liatris punctata Hook. (Asteraceae) densities were reduced only by atrazine and sulfentrazone.