Postemergence-applied, grass-active herbicides registered for use in the landscape were applied over-the-top of four ornamental grass species to evaluate tolerance in 1990 and 1991. All herbicides caused some injury to all grass species. Growth indices of dwarf fountain grass (Pennisetum alopecuroides L.K. Spreng. ‘Hameln)’ and pampas grass (Cortaderia selloana Schult. & Schult. f. Asch & Graebn. ‘Rosea’) treated with the low rate of Poast (sethoxydim) was similar to that of the nontreated plants in both years. Acclaim (fenoxaprop-ethyl) caused less injury to purple maiden grass (Miscanthus sinensis Anderss. ‘Purpurescens’) and maiden grass (M. sinensis Anderss ‘Gracillimus’) than Poast and Fusilade 2000 (fluazifop). Both Acclaim rates resulted in similar growth indices to that of nontreated plants. Flowering was reduced in three of the four grass species with all grass active herbicide treatments; the fourth species did not flower.
2Professor, Associate Professor, Assistant Professor and Research Associate,respectively.