Effects of Cupric Hydroxide-Treated Containers on Growth of Four Southwestern Desert Landscape Trees
Chris A. Martin and Sheila Bhattacharya
Abstract: Seedling liners of four southwestern desert landscape trees, Acacia smallii, Acacia stenophylla, Cercidium praecox, and Prosopis chilensis, were potted into black polyethylene containers either painted on the inner wall with a latex paint containing cupric hydroxide [Cu(OH)2] or unpainted. Tree seedlings were then grown for five months in an outdoor container production nursery and evaluated for effects of Cu(OH)2-treated containers on tree growth. No foliar copper toxicity symptoms were observed on any species during the study. In comparison with unpainted containers, Cu-treated containers increased root branching frequency, reduced shoot extension, and lowered the number of primary shoot lateral branches of sweet acacia and shoestring acacia. Cu-treated containers also decreased height of shoestring acacia. Chilean mesquite grew taller and larger with increased shoot and root dry weights in Cu-treated containers in comparison with those in unpainted containers. However, effects of Cu-treated containers on growth of Chilean mesquite were not related to any changes in root branching frequency. Growth of palo brea and root-to-shoot ratios of all four tree species were not affected by Cu-treated containers.