Effect of Soil Type and Nitrogen Rate on Growth of Annual and Perennial Landscape Plants in Florida

Abstract

Previous research indicated that acceptable quality annual and perennial plant species can be grown in the landscape with low nitrogen (N) inputs. However, information on the impact of soil conditions and N use by ornamental plants grown in central Florida is lacking in the literature. Our objective was to evaluate plant growth and quality response of eight warm-season annuals, seven cool-season annuals, and four herbaceous perennial species to a range of N fertilizer rates when plants were grown in landscape beds containing native field soil or subsoil fill. A slow-release N source (42N–0P–0K) was applied every 12 weeks at annual N rates of 3, 5, or 7 lb/1000 ft2 for a period of 18 weeks (annual species) or 1, 3, or 5 lb/1000 ft2 for a period of 54 weeks (perennial species). Plants were evaluated for aesthetic quality every 6 weeks and shoot dry weight was measured at completion of the experiment. Dry weight production and aesthetic quality of most species evaluated was unaffected by N rate. For several species, shoot dry weight was higher when planted in the field plots containing native soil [alyssum (Lobularia maritima) ‘Bada Bing White’ wax begonia (Begonia ×semperflorens-cultorum), dahlberg daisy (Thymophylla tenuiloba), ‘Survivor Hot Pink’ geranium (Pelargonium ×hortorum), gomphrena (Gomphrena globosa), ‘Blue Puffs Improved’ (‘Blue Danube’) ageratum (Ageratum houstonianum), blanket flower (Gaillardia pulchella), goldenrod (Solidago chapmanii), ‘Mystic Spires’ salvia (Salvia longispicata ×farinacea)]. Quality response to soil condition was mixed over the course of the study. Several species performed as well (or better) in the field as when planted in the subsoil fill soils. These results illustrate that some landscape plant species are able to survive and thrive under various soil and fertility conditions. These “tougher” species may be good choices for installation in landscapes with marginal native soils or disturbed urban landscape soils.