Effects of Commonly-Used Herbicides on Establishing and Mature Kurapia (Lippia nodiflora L.).

Kurapia (Lippia nodiflora L.) is a broadleaf groundcover selected and developed in Japan that has recently been recognized for its low water use and salinity tolerance characteristics.  Kurapia use is now increasing in California landscapes, but little is known about its tolerance to pre- and postemergence herbicides during or after establishment.  Our objective was to evaluate Kurapia tolerance to 15 commercially available herbicides at various stages of establishment.  Kurapia plugs were installed in March 2015 in two California locations (Riverside and San Luis Obispo).  All herbicides were applied at labeled rates at 1, 6, or 12 weeks after planting Kurapia plugs in each location.  Kurapia injury was visually estimated at 1, 2, 4, and 6 weeks after treatment for each herbicide timing, and percent Kurapia ground cover was visually estimated every two weeks from March through July.  Metolachlor, prodiamine, and fluazifop were generally the least injurious at each application timing in San Luis Obispo and Riverside, whereas triclopyr, indaziflam, halosulfuron, 2,4-D + MCPP + dicamba + carfentrazone-ethyl, and thiencarbazone + foramsulfuron + halosulfuron were most injurious.  Kurapia response to isoxaben, sulfosulfuron, mesotrione, quinclorac, clopyralid, MCPP, and thiencarbazone + iodosulfuron + dicamba was variable among application timings and between sites.