Pendimethalin has been registered in the United States since 1994 for uses in and around environmental horticulture plants in production nurseries and in landscapes. Between 1981 and 2023, the IR-4 Project has conducted 559 trials using two granular formulations (Corral 2.68G and Pendulum 2G), three liquid formulations (Pendulum AquaCap, Pendulum 3.3EC and Prowl 4E) and a wettable dry granular formulation (Pendulum WDG). Between 2014 and 2018, Pendulum 2G was examinined for use on ornamental grasses. During 2020 and 2021, Pendulum 2G was a part of a project to examine options for field in-ground cutflower growers. This summary contains data across all the reports available through IR-4 since screenings began in 1981.
Two hundred twenty-four (224) genera or species have been screened with the six different pendimethalin formulations. Sixty-three plant species or genera exhibited no or minimal, transitory phytotoxicity to over the top applications of Corral 2.68G and Pendulum 2G formulations, eight plant species or genera exhibited no or minimal, transitory phytotoxicity to over the top applications of Pendulum AquaCap and Pendulum WDG formulations, and six species or genera exhibited no or minimal, transitory phytotoxicity to over the top applications of Pendulum 3.3 EC or Prowl 4E. This research has been beneficial for adding new crop to the Pendulum 2G and Pendulum WDG formulations.