Concern among water management officials, researchers, and the public regarding landscape water consumption has escalated as demands on potable water supplies increase in Florida and other populated regions (Archer, 2002; Beeson and Gilman, 1992; Salamone, 2002). Interested parties continually seek new and innovative measures to reduce consumption; however, traditional methods of water restriction and plant selection prevail. Restrictions in Florida vary depending on location, generally permitting 30 to 60 d of daily irrigation for landscape establishment and weekly to biweekly applications for the postestablishment phase (Bodle, 2001; Florida Department of State, 2007). Established landscapes can be maintained with minimal supplemental irrigation if plant selection is appropriate for site conditions (Sachs et al., 1975).
When choosing landscape plant material, native species are promoted as drought tolerant by everyone from the popular media to university professionals (Bodle, 2001; Haehle, 2004; Hostetler et al., 2003). Although many taxa are classified as drought resistant, these classifications often are based upon anecdotal observations of plant performance in landscape plantings (Garcia-Navarro et al., 2004; Levitt et al., 1995). Direct comparisons among native and introduced species using physiological measures are limited to support or refute such recommendations.
Garcia-Navarro et al. (2004) found mixed results evaluating relative water use among two native [vine hill manzanita (Arctostaphylos densiflora) and texas sage (Leucophyllum frutescens)] and two introduced [vanhoutte spirea (Spiraea vanhouteii) and laurustinus (Viburnum tinus)] species with neither native nor nonnative outperforming the other. Water use efficiency (WUE) increased as irrigation frequency increased, yet shoot and root dry weight were unaffected for nonnative red bird-of-paradise (Caesalpinia pulcherrima). In comparison, WUE declined and growth increased with increased frequency for native blue pale verde (Cercidium floridum) (Stabler and Martin, 2000). Zollinger et al. (2006) evaluated three native and three introduced herbaceous perennials for growth and aesthetic quality in response to irrigation frequency. In general, shoot or root dry weight declined with decreased frequency for all taxa except ‘Rondo Mix’ penstemon (Penstemon barbatus var. praecox nanus rondo), a native species. Furthermore, visual quality was ranked highest on ‘Rondo Mix’ penstemon under water-limited conditions. Several studies comparing WUE or growth among grass species yielded similar results. Glenn et al. (1998) reported similar WUE among native and introduced species, but Blicker et al. (2003) found greater growth for native species. Bodle (2001), Haehle (2004), and Hostetler et al. (2003) suggest that native species should outperform introduced species in their native habitat. However, species performance is unknown in maintained environments such as commercial and residential landscapes (Anella, 2000; Knox, 1990). The objective of this study was to evaluate postestablishment growth and aesthetic quality of commonly used native and exotic shrubs under irrigated and nonirrigated landscape conditions.
Allcock, K.G. 2002 Effects of phosphorus on growth and competitive interactions of native and introduced species found in White Box woodlands Austral Ecol. 27 638 646
Archer, M. 2002. We must heed scary warnings about aquifer. Orlando Sentinel 17 Feb.:A1.
Beeson R.C. Jr & Gilman, E.F. 1992 Diurnal water stress during landscape establishment of slash pine differs among three production methods J. Arboriculture 18 281 286
Blicker, P.S., Olson, B.E. & Wraith, J.M. 2003 Water use and water-use efficiency of the invasive Centaurea maculosa and three native grasses Plant Soil 254 371 381
Devitt, D.A., Morris, R.L. & Neuman, D.S. 1994 Evapotranspiration and growth response of three woody ornamental species placed under varying irrigation regimes J. Amer. Soc. Hort. Sci. 119 452 457
Devitt, D.A., Neuman, D.S., Bowman, D.C. & Morris, R.L. 1995 Water use of landscape plants grown in an arid environment J. Arboriculture 21 239 245
Florida Department of State 2007 40D-22: Year-round water conservation measures 5 Aug. 2007 <www.flrules.org/gateway/chapterhome.asp?chapter=40D-22>.
Fogarty, G. & Facelli, J.M. 1999 Growth and competition of Cytisus scoparius, an invasive shrub, and Australian native shrubs Plant Ecol. 144 27 35
Garcia-Navarro, M.C., Evans, R.Y. & Montserrat, R.S. 2004 Estimation of relative water use among ornamental landscape species Sci. Hort. 99 163 174
Gilman, E.F., Yeager, T.H. & Weigle, D. 1996 Fertilizer, irrigation, and root ball slicing affects burford holly growth after planting J. Environ. Hort. 14 105 110
Glenn, E., Tanner, R., Mendez, S., Kehret, T., Moore, D., Garcia, J. & Valdes, C. 1998 Growth rates, salt tolerance and water use characteristics of native and invasive riparian plants from the delta of the Colorado River, Mexico J. Arid Environ. 40 281 294
Haman, D.Z., Smajstrla, A.G. & Pitts, D.J. 2005 Efficiencies of irrigation systems used in Florida nurseries University of Florida Institute of Food and Agricultural Sciences Coop. Ext. Serv. Bul. 312
Harris, R.W., Clark, J.R. & Matheny, N.P. 2004 Arboriculture: Integrated management of landscape trees, shrubs, and more Prentice Hall Upper Saddle River, NJ
Hostetler, M., Klowden, G., Miller, S. & Youngentob, K. 2003 Landscaping backyards for wildlife: Top ten tips for success University of Florida Institute of Food and Agricultural Sciences Electronic Data Information Source Publ. No. UW175
Knox, G. 1990 Landscape design for water conservation University of Florida Institute of Food and Agricultural Sciences Electronic Data Info. Source Publ. No. ENH72
Leishman, M.R. & Thomson, V.P. 2005 Experimental evidence for the effects of additional water nutrients and physical disturbance on invasive plants in low fertility Hawkesbury Sandstone soils, Sydney, Australia J. Ecol. 93 38 49
Levitt, D.G., Simpson, J.R. & Tipton, J.L. 1995 Water use of two landscape tree species in Tucson, Arizona J. Amer. Soc. Hort. Sci. 120 409 416
Littell, R.C., Milliken, G.A., Stroup, W.W., Wolfinger, R.D. & Schabenberger, O. 2006 SAS for mixed models 2nd ed SAS Institute Inc Cary, NC
O'Dwyer, C. & Attiwill, P.M. 1999 A comparative study of habitats of the golden sun moth Synemon plana Walker (Lepidoptera: Castniidae): Implications for restoration Biol. Conserv. 89 131 141
Salamone, D. 2002. A drying oasis series: Florida water crisis chapter 1. Orlando Sentinel 3 Mar.:A1.
Sanford, N.L., Harrington, R.A. & Fownes, J.H. 2002 Survival and growth of native and alien woody seedlings in open and understory environments For. Ecol. Manage. 183 377 385
Scheiber, S.M., Gilman, E.F., Paz, M. & Moore, K.A. 2007 Irrigation affects landscape establishment of burford holly, pittosporum, and sweet viburnum HortScience 42 344 348
Stabler, L.B. & Martin, C.A. 2000 Irrigation regimes differentially affect growth and water use efficiency of two southwest landscape plants J. Environ. Hort. 18 66 70
Trenholm, L.E., Gilman, E.F., Knox, G.W. & Black, R.J. 2002 Fertilization and irrigation needs for Florida lawns and landscapes University of Florida Institute of Food and Agricultural Sciences Electronic Data Info. Source Publ. No. ENH860
Zollinger, N., Kjelgren, R., Cerny–Koenig, T., Kopp, K. & Koenig, R. 2006 Drought responses of six ornamental herbaceous perennials Sci. Hort. 109 267 274