Evaluating Form and Function of Groundcovers and their Environmental Impacts in Louisiana Landscapes

Abstract

Increasing environmental concerns are encouraging the adoption of sustainable landscapes that have environmental, social, and financial benefits. Ornamental groundcover systems are touted as sustainable landscape features due to the associated decreased demand of water, fertilizer, pesticide, and maintenance; however, limited research exists on soil property effects, planting density, weed density, or consumer preferences of groundcovers. This study was aimed to gain a more thorough understanding of ornamental groundcovers systems and their environmental impacts. The effects of groundcover growth habit (matting; bunching) and irrigation delivery (micro spray; overhead) on soil temperature, volumetric water content (VWC), and electric conductivity (EC) along with impacts on weed growth, soil microbial communities, and plant coverage were measured. Furthermore, twelve traditional and non-traditional groundcover species’ vegetative coverage and visual quality were assessed under optimal and suboptimal planting densities. Soil temperatures were lowest under groundcover species with a matting growth habit, and to a lesser extent, bunching species, in comparison to fallow systems. Micro spray irrigation decreased VWC values with matting species exacerbating this decrease when compared to overhead irrigation delivery. Plant type did not influence EC values, however micro spray irrigation produced significantly increased EC values perhaps due to increased leaching of the overhead irrigation. Micro spray irrigation along with matting growth habits decreased weed density greater than bunching species or overhead irrigation. Annual and most tender perennial groundcover species can tolerate suboptimal planting densities to achieve vegetation coverage values analogous to optimal densities, while hardy perennials cannot. A consumer survey revealed non-traditional groundcover species were preferred over industry standards in both aesthetic and coverage quality. Plant species nor irrigation affected the soil microbial communities. Groundcovers species with increased vegetative coverage along with a targeted irrigation regime can reduce soil temperature, moisture, and weeds. Suboptimal planting densities can accomplish comparable results to optimal densities, with plant spacing dependent on species selection, thus decreasing landscape plant material costs while maintaining consumer satisfaction. Residential and commercial landscapes can incorporate groundcovers to increase their sustainability while maintaining visual qualities associated with more traditional landscapes.