In a preliminary experiment a single treatment of 2 kg ha−1glyphosate was found to be as effective as higher rates of application in reducingCyperus rotundusshoot numbers. Single applications of 11–2 kg ha−1bromacil and 976 kg ha−1methyl bromide were compared with multiple applications of 2 kg ha−1glyphosate, 4.5 kg ha−12,4‐D, 4 kg ha−1EPTC, 2.4 kg ha−1vernolate, 5 kg ha−1pebulate, 2–9 kg ha−1amitrole and eight successive rotary hoeings during dry weather, all over a 19‐month period. Most treatments reduced shoot and tuber populations and tuber weights but the most efficient treatments were bromacil, cultivation, glyphosate and 2,4‐D. At the end of the experiment the percentage of tubers with shoots was similar for many treatments but was higher on the thiocarbamate treatments and tended to be lower on the glyphosate treatment. The percentage of dormant or moribund tubers was higher on the glyphosate treatment than on other treatments. The greatest effect of most treatments was on the shallowest tubers (0–10 cm), except for 2,4‐D which affected tubers uniformly over the three depth ranges studied.