Responses of Landscape Groundcovers to Minimum Irrigation

Abstract

Abstract Four irrigation regimes based on percentages of real-time reference evapotranspiration (ET0) were applied to six widely used species of landscape groundcovers (Baccharis pilularis ‘Twin Peaks’, Drosanthemum hispidum, Vinca major, Gazania rigens v. leucolaena ‘Yellow Cascade’, Potentilla tabernaemontanii, and Hedera helix ‘Needlepoint’) during a 17-month period in Irvine, CA. Irrigation treatments (50%, 40%, 30% and 20% of ET0) were applied when accumulated real-time ET0 × treatment percentage reached 4.0 cm (1.6 in). Although the response to irrigation treatment was species dependent, Baccharis, Drosanthemum, and Hedera maintained at least minimally acceptable visual quality with applied water equal to 20% ET0, while Vinca required a minimum of 30% ET0. Acceptable visual quality of Gazania and Potentilla were not maintained at any treatment. Visual quality of Potentilla was better at ET0 greater than or equal to 30% ET0, but visual quality of Gazania was not improved with more water.