Zoysia japonica ‘Meyer’, is frequently used as lawn and golf turf in the upper South because of its excellent summer qualities and superior winter hardiness compared to other warm-season grasses. Planting is mostly by vegetative methods to obtain uniform turf. Planting in existing turf slows spread of zoysiagrass because of plant competition. The objective of this study was to selectively inhibit growth, with growth retardants, of competing Kentucky bluegrass, Poa pratensis L. ‘Baron’, turf into which ‘Meyer’ zoysia had been planted. Mefluidide, at a rate of 0.028 kg/ha, enhanced the spread of zoysiagrass in bluegrass by 20% compared with untreated plots during the 1st year, without serious injury to the bluegrass turf. Fertilizing zoysiagrass plugs with UF (38N-0-0) also increased zoysiagrass cover by 10-20% during the 1st 2 years compared with control plots or those fertilized with urea after zoysiagrass had been transplanted. Irrigation location had no effect on zoysiagrass spread, possibly because of the relatively mild and wet summers of 1981-82 when minimal irrigation was needed to maintain good quality turf. Results of this study show that growth retardants in combination with certain N fertilization techniques can enhance the spread of transplanted zoysiagrass without serious injury to the existing bluegrass sward. This is attributed to selectively decreased growth of bluegrass and, therefore, partial elimination of bluegrass competition from the bluegrass or, to possible stimulation of zoysiagrass by mefluidide.
Professor, Horticulture Dept.
Received for publication 27 July 1983. Research supported by Univ. of Missouri Agricultural Experiment Station, Columbia, MO 65211. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact.