Ornamental Landscape Performance of Native and Nonnative Grasses under Low-input Conditions

SUMMARY. Full sun trial gardens (full sun) were established at Leon County (LC) and Santa Rosa County (SRC), Florida, to evaluate the effect of site on horticultural performance traits pertinent to landscape use (long-term growth, flowering, vigor, overall quality, and survival) of native and nonnative warm season grasses when grown under low-input landscape conditions over a 3-year period. The gardens contained landscape fabric- (LC) or plastic (SRC)-covered rows, with the synthetic mulch at each site covered by 4 inches of hardwood chip mulch. Fifteen native and eight nonnative grass species, and cultivars were evaluated as were the two grass-like species black floweringsedge(Carex nigra) and narrowleafsilkgrass (Pityopsis graminifolia), anative dicot with grass-like foliage. Many of the native species were derived from seeds or plants collected from naturally occurring populations in Florida, and other species or cultivars were obtained from commercial sources. Based on quality ratings and survival, a majority of the species and cultivars were rated as at least being marginally acceptable for 2 years or more, but only six species and cultivars were rated as excellent or good over all 3 years. Four of these six species were native, with 100% survival at both sites occurring only for purpletop tridens (Tridens flavus ). The other three native species, gulf hairawn muhly, (Muhlenbergia capillaris var. filipes), ‘Alamo’ switchgrass (Panicum virgatum), and indian woodoats (Chasmanthium latifolium )h ad high rates of survival. Porcupine grass (Miscanthus sinensis ‘Strictus’) and ‘Cabaret’ silver grass (M. sinensisssp.condensatus)weretheonlytwononnativespeciesdemonstratingpotential for long-term performance in a low-input landscape at both sites. Three of the four cultivars of miscanthus (Miscanthus spp.) survived the entire evaluation period in SRC, while two cultivars sufferedlossesonlyinLC, demonstrating the importanceof site effects on the long-term performance of individual species or cultivars of grasses. Chalky bluestem (Andropogon capillipes) (Orange County, FL), sand lovegrass (Eragrostis trichoides), giant silver grass (Miscanthus ·giganteus), and bamboo muhly (Muhlenbergia dumosa) each survived 3 years at one site but only 1 year at the other site. Pineland threeawn (wiregrass) (Aristida stricta), ‘Red Baron’ cogon grass (japanese blood grass) (Imperata cylindrical), ‘Hameln’ fountain grass (Pennisetum alopecuroides),blackfloweringfountaingrass(P.alopecuroides‘Moudry’),and‘Feesey Form’ ribbon grass (Phalaris arundinaceae) were categorized as marginal for low-input landscapes and could only be considered short-term perennials under the conditions of this test. ‘Morning Light’ silver grass (M. sinensis), coastal bluestem (Schizachyrium maritimum), and ‘Lometa’ indiangrass (Sorghastrum nutans) had good2-yearlandscapeperformanceandsurvivedatleast2yearsatbothsites.Bigtop lovegrass (Eragrostis hirsuta), silver plumegrass (Saccharum alopecuroides), and lopsided indiangrass (Sorghastrum secundum) were categorized as having excellent 1-year landscape performance and have potential for short-term performance under low-input conditions. Chalky bluestem (Andropogon capillipes) (SRC), black flowering sedge, ‘Heavy Metal’ switchgrass (Panicum virgatum), and narrowleaf silkgrass were categorized as having good 1-year landscape performance.