Postestablishment Landscape Performance of Florida Native and Exotic Shrubs Under Irrigated and Nonirrigated Conditions

Abstract

<jats:p>Although new and innovative measures to reduce landscape water consumption are being sought, traditional methods of water restrictions and plant selection prevail. Species native to North America are often promoted as drought tolerant with little information to support or refute such claims. Furthermore, species performance is unknown in maintained environments such as commercial and residential landscapes. Thus, 10 native and 10 exotic species, commonly used in landscapes, were evaluated independently for postestablishment growth and aesthetics under irrigated and nonirrigated landscape conditions. Growth indices were recorded monthly, with dieback and plant density evaluated at termination of the experiment. At termination of the experiment, canopy size of eight native [beautyberry (<jats:italic>Callicarpa americana</jats:italic>), fringe tree (<jats:italic>Chionanthus virginicus</jats:italic>), yaupon holly (<jats:italic>Ilex vomitoria</jats:italic> ‘Nana’), virginia sweetspire (<jats:italic>Itea virginica</jats:italic>), wax myrtle (<jats:italic>Myrica cerifera</jats:italic>), chickasaw plum (<jats:italic>Prunus angustifolia</jats:italic>), saw palmetto (<jats:italic>Serenoa repens</jats:italic>), and coontie (<jats:italic>Zamia floridana</jats:italic>)] and eight exotic [golden dewdrop (<jats:italic>Duranta erecta</jats:italic>), cape jasmine (<jats:italic>Gardenia augusta</jats:italic>), crape myrtle (<jats:italic>Lagerstroemia indica</jats:italic>), oleander (<jats:italic>Nerium oleander</jats:italic>), japanese pittosporum (<jats:italic>Pittosporum tobira</jats:italic>), indian hawthorn (<jats:italic>Rhaphiolepis indica</jats:italic>), sweet viburnum (<jats:italic>Viburnum odoratissimum</jats:italic>), and sandankwa viburnum (<jats:italic>V. suspensum</jats:italic>)] species were similar for irrigated and nonirrigated treatments. Irrigation resulted in larger canopy sizes for two native [walter's viburnum (<jats:italic>V. obovatum</jats:italic>) and inkberry (<jats:italic>I. glabra</jats:italic>)] and two nonnative [japanese privet (<jats:italic>Ligustrum japonicum</jats:italic>) and fringe flower (<jats:italic>Loropetalum chinensis</jats:italic>)] species. Among the native species with larger canopy sizes under irrigated conditions, all are indigenous to swamps and streams. With the exception of virginia sweetspire, plant density and dieback were similar for irrigated and nonirrigated plants of all taxa examined. Irrigated virginia sweetspire plants had higher plant density and dieback ratings than nonirrigated plants. Results indicate that, aesthetically, irrigated and nonirrigated plants were similar. Data emphasize the importance of selecting plant material adapted to existing environmental landscape conditions.</jats:p>

Native and Non-native Shrub Post-transplant Performance under Low-volume Irrigation in Three Hardiness Zones

“…Our data also suggest that there were no differences in canopy growth or aesthetic quality of native versus non-native shrubs at any of the planting locations (Tables 2 and 3). Our results are similar to those of Scheiber et al (2008), who found that neither native species nor non-native species were, as a group, more responsive to irrigation. Scheiber et al (2008) reported that growth of two of 10 Florida natives and two of 10 non-natives increased when irrigated (daily for 17 d, then every 2 d for 7 weeks, then every 7 d).…”

“…Scheiber et al (2008) reported that growth of two of 10 Florida natives and two of 10 non-natives increased when irrigated (daily for 17 d, then every 2 d for 7 weeks, then every 7 d). Enhanced growth of irrigated shrubs seemed to be associated with species habitat preference because all species that increased in growth as a response to irrigation were endemic to wet habitats (e.g., swamps and streams) (Scheiber et al, 2008).…”

“…For example, Scheiber et al (2008) reported no differences in growth response or aesthetic appearance due to irrigation treatment for 8 of 10 native and 8 of 10 non-native species grown in northern Florida. Only two species, which were endemic to swamps and streams, showed increased growth in response to irrigation compared with no irrigation (Scheiber et al, 2008).…”

“…In fact, research indicates that water use is more likely to be a function of endemic habitat (Scheiber et al, 2008), shrub morphology (King and Wilson, 2006), plant growth rate (Fitzpatrick, 1983), and shrub maturity (Stabler and Martin, 2000) than its native range. For example, Scheiber et al (2008) reported no differences in growth response or aesthetic appearance due to irrigation treatment for 8 of 10 native and 8 of 10 non-native species grown in northern Florida. Only two species, which were endemic to swamps and streams, showed increased growth in response to irrigation compared with no irrigation (Scheiber et al, 2008).…”

Water Conservation Benefits of Long‐Term Residential Irrigation Restrictions in Southwest Florida

“…It was assumed that each landscape consisted of 79% well‐watered turfgrass and 21% ornamental plant beds (Haley & Dukes ). The irrigation requirement of the ornamental plant beds, which typically don't need supplemental irrigation after six to 12 months of planting, was assumed to be zero (Shober et al , Scheiber et al ).…”