Abstract

Two experiments evaluated the effects of preemergence herbicides on growth of pampas grass [Cortaderia selloana (Schult. and Schult f.) Asch. and Graebn.] applied after transplanting from 72-cell packs into 3.8 liter (#1) containers. Ronstar (oxadiazon) and Regal O-O (oxadiazon + oxyfluorfen) applied at the manufacturers' recommended rates caused little or no injury. Ornamental Weedgrass Control (pendimethalin), Pendulum 2G (pendimethalin), Pendulum 60 WDG (pendimethalin), Surflan 4AS (oryzalin), Rout (oryzalin + oxyfluorfen), and Factor 65 WG (prodiamine) suppressed root development in the upper 5.1 cm (2 in) of the container medium in both experiments. Application of Surflan 4AS resulted in 100% and 70% mortality of plants in the two experiments, respectively. Lodging was greatest with Factor 65 WG (100% and 90% in the two experiments) and Pendulum 60 WDG (50% in both studies). Some lodging occurred with the application of all dinitroaniline herbicides in the two studies.