EFFECT OF GRAYWATER ON GROWTH AND APPEARANCE OF ORNAMENTAL LANDSCAPE PLANTS

Our objective was to determine the potential reuse of wastewater from laundry and kitchen facilities for irrigating residential landscapes. The impacts of wastewater generated by laundry and kitchen facilities in residential dwellings on survival, growth, and appearance of eight ornamental plants were evaluated in a greenhouse study. Kitchen wastewater killed or severely injured every species included in the study. Survival was 100% for all plants irrigated with laundry wastewater, laundry wastewater amended with CaCl2 or tap water. Plant response to laundry wastewater and laundry wastewater amended with CaCl2 was plant specific. Top (aerial tissue) dry weights of ‘Super Olympia Red’ begonia, ‘Celebrity Neon’ petunia, ‘Sunglow’ azalea, willow oak, and loblolly pine irrigated with laundry wastewater and laundry wastewater amended with CaCl2 were not significantly different from plants irrigated with tap water. Top dry weight of ‘Honeybells’ hosta was greatest with laundry wastewater, whereas hostas irrigated with laundry wastewater amended with CaCl2 was significantly smaller than laundry wastewater and tap water. Top dry weight of ‘Compacta’ holly was significantly reduced by laundry wastewater and CaCl2 amended laundry wastewater compared to tap water. Compared to tap water, visual appearance of all plants except 'Sunglow' azalea was reduced by laundry wastewater, whereas only ‘Super Olympia Red’ begonia and willow oak were reduced by CaCl2 amended laundry wastewater. Data herein suggest that CaCl2 amended laundry wastewater has potential for use in irrigating landscape plants in North Carolina, whereas wastewater from dishwashing machines is not suitable at this time.