Irrigating Landscape Bedding Plants and Cut Flowers With Recycled Nursery Runoff and Constructed Wetland Treated Water

Abstract

Abstract Direct nursery runoff (runoff), wetland treated recycled nursery runoff (recycled), and a municipal water source (tap) with and without elevated salt (NaCl targeted injection to 3.0 dS·m−1) levels were tested as potential drip irrigation sources for production of in-ground cut flower crops and landscape bedding plants. Two species of cut flowers, Helianthus annuus L. ‘Mammoth’ (sunflower) and Gladiolus hortulanus L. ‘Tout A Toi’ (gladiolus), and two bedding plants, Catharanthus roseus G. Don ‘Pacifica Red’ (vinca) and Zinnia elegans N.J. von Jacquin ‘Lilliput Mixed Colors’ (zinnia), were established in trial beds irrigated with the four water treatments during the summer of 2001 as a warm season experiment. A second experiment was conducted from November 2001 to May 2002 to investigate growth and flowering responses of two species of cut flower crops [Consolida ambigua (L.) P Ball & V Heywood (larkspur) and Narcissus tazetta L. ‘Galilea’ (paperwhite narcissus)] and two bedding plants [Antirrhinum majus L. ‘Montego Mix’ (snapdragons) and Viola × wittrockiana H. Gams ‘Crown Mix’ (pansies)]. Marketable crops of sunflower, paperwhite narcissus, and larkspur were produced with all four water treatments. Direct nursery runoff, recycled wetland treated water, and NaCl spiked water that were high in soluble salts during the heat of summer reduced yield and inflorescence diameter with sunflowers, but only slightly reduced inflorescence quality and had no effect on yield of paperwhite narcissus. These three treatments also affected stand density, but not yield of cut larkspur inflorescences in the cool season. Irrigation with water containing elevated NaCl levels reduced flower counts on pansies and growth indices on pansies and snapdragons over much of the growing season, but reduced snapdragon flowering only in spring. Vinca was unaffected by the irrigation treatments. Zinnia survival and flowering were reduced or delayed by irrigation with recycled or elevated NaCl water.