The 2012 ASHS Annual Conference

Many flowering shrubs used in the landscape require routine pruning or shearing to keep their shape neat and compact. Pruning is a significant expenditure of time and a major labor cost for the landscape service industry. In addition, over half of the states in the U.S. have passed laws against disposing of yard wastes in landfills, which has increased the interest in using PGRs to reduce pruning or the amount of clippings. Application rates and frequency of Cutless .33G (flurprimidol) were studied in two studies for managing growth of two loropetalum cultivars, Merlot Lace and ZhuZhou in the landscape. Results indicated that Cutless at 14 lbs/1000 ft² applied once in the spring is effective on controlling shoot growth from spring to summer for both cultivars. Additional application in August provide no or limited growth control compared to single application in April. However, a fall application improved plant visual quality during early spring of the next growing season. Darker color leaves were confirmed by a chlorophyll content meter. Higher fertilization rates improved plant visual quality but resulted in taller plants even at high rate of flurprimidol.