Effect of Chemical Growth Retardants on Turfgrass Morphology¹

Abstract

Abstract Studies on chemical growth retardation of turfgrasses have often dealt with chemical effects on aerial parts with little or no attention devoted to root development, or to rhizome and tiller number. If a retardant is to be used for grass growth control, long‐term effects on subterranean as well as aerial parts must be considered. Greenhouse experiments were conducted to determine the influence of 19 growth retardant treatments on several morphological growth parameters of tall fescue ( Festuca arundinacea Schreb.) and Kentucky bluegrass ( Poa pratensis L.). Most growth retardant treatments which caused aerial growth reductions also restricted root spread, volume, and dry weight. Some retardants also reduced tall fescue and Kentucky bluegrass tiller number and bluegrass rhizome development. The implications of these results are serious in terms of maintainance of long‐term stand of vigorous turf. Growth retardants for turf must be developed which recard top growth without detrimentally affecting root, rhizome, or tiller development.