Disclosed is an apparatus (10) suitable for controlling vegetation. The apparatus comprises a hot-liquid reservoir (28) containing water, release means (38) connected to the hot-liquid reservoir and at least one nozzle (74) connected to the reservoir via the release means. The apparatus includes a heating means (34) to heat the liquid in a plurality of stages in succession to a temperature above 102 degrees Celcius such that the pressure in the reservoir is above atmospheric pressure. In use, the liquid does not boil until it emerges from the nozzle, where it combines with a surfactant to for a foam that contains steam. This foam containing steam advantageously acts as a thermal blanket to further prolong heat exposure to the vegetation to be controlled. The apparatus is mounted on a vehicle or a vehicle drawn wheeled trolley or trailer. A method of controlling vegetation is also disclosed.
