The 2012 ASHS Annual Conference

Rhizoma peanut (Arachis glabrata Benth.) has received little attention for its potential use as an ornamental groundcover although it has been used almost exclusively as a forage crop since the 1970s.  This study represents the first attempt at characterizing attributes of rhizoma peanut for ornamental use.  These attributes include low stature, high visual quality, flower production, drought, pest, and disease resistance, and no need for nitrogen inputs.  Additionally, variable rates of cover and mature heights among selections warrant a comparison to quantify ornamental attributes of new and previously released rhizoma peanut selections.   Furthermore, successful cultivation of rhizoma peanut in a shaded environment would allow a greater diversity of landscape habitats to be utilized.  Individual plots of 16 cultivars were replicated four times in a completely randomized block design at two Florida locations.  A split-plot design was chosen, with cultivar as the main plot and shade treatment as the sub plot.  Shade treatments were created by covering half of each plot with 30% shade cloth.  Plots were evaluated bi-weekly over two growing seasons for coverage, canopy height, number of flowers, and visual quality.  Locations were not directly comparable due to differences in planting year.  During the first (establishment) year, mean height was less than that of established (second year) plots.  Mean height was affected more by rhizoma peanut selection than by shade treatment or location.  Rate of cover was much greater for established plots (over 1 year old) than establishing plots.  Rhizoma peanut selection had a strong effect on rate of cover and total coverage.  Shaded plots were slower to achieve full coverage compared to full sun plots and they were also slower to exhibit low temperature induced defoliation and die-back.  After 2 years of establishment, well-drained sandy soils reduced coverage more than clay soils with greater water holding capacity.   Flower number was most influenced by selection and was significantly reduced in shade.  Flower number was greatest during the establishment year, and was reduced in the second year due to increased height which obscured flowers.  Visual quality was influenced more by selection than shade treatment, location, or year.  Generally, cultivar performance was not significantly different between sun and shade, suggesting rhizoma peanut is adaptable to a wide range of shade environments.  This study provides evidence that several selections of rhizoma peanut are suitable for ornamental use, evidenced by a fast rate of cover, low height, high visual quality, and prolific flowering.