Management information
Nuzzo (1997) reports that C. arvense should be removed from high quality natural areas when it is first observed. The plant is very tenacious and difficult to control once established. In lower quality areas, management effort should be influenced by the extent of invasion; greater effort is warranted in areas that have new and/or small invasions, which are more likely to be eliminated or contained. Management programs should be designed to kill established clones since the species spreads primarily by vegetative expansion of the root system. It takes at least two growing seasons to determine whether a particular control method is effective. At this time, there are no control methods suitable for wide-spread use in natural areas that eradicate, rather than reduce C. arvense. Control efforts may be more successful when the plant is under environmental stress. The plant is drought and flood sensitive, and its roots are cold-sensitive. Cutting or applying herbicide to shoots after a very severe winter may add sufficient stress to kill plants. For details on chemical, physical and biological control options, please see management information.