Poor economic return from perennial aromatic grasses during a planting year results from the high cost of cultivation, on account of planting, and lower yields, largely due to slow crop growth rate and high vulnerability of aromatic grasses to weeds, which are poorly managed In the absence of suitable weed control measures. Field experiments were established in July 1982 to examine the suitability of organic mulch (distillation waste of citronella Java) and herbicides in three important perennial aromatic grasses, citronella Java(Cymbopogon winterianusJowitt), lemongrass(C. flexuosus(D.C.) Stapf) and palmarosa (C.martiniiStapf var.motia) fortwo harvest years (1981–82 and 1982–83) under a subtropical climate at Lucknow. Weeds caused an average 40% reduction in herb and oil yields in the first harvest year as against 6% In the second. Organic mulch 3 t/ha, oxyfluorfen 0–5 kg/ha, diuron 1.5 kg/ha and simazine 1.5 kg/ha gave herb and oil yields equal to weed‐free check, and proved superior to the conventional method, which yielded 20% less than weed‐free check in the first harvest year. Organic mulch was found to be most competitive over other promising treatments. Palmarosa followed by lemongrass had a better weed‐suppressing effect than citronella Java.