Vegetation such as a weed (45) may be controlled by generating a foam comprising air and an aqueous solution comprising a surfactant； dispensing the foam so as to coat at least a base part of the weed that is to be controlled； and then injecting hot water into the foam (46) so as to contact the weed (45) below or within the coating of foam (46) The hot water causes the weed (45) to wilt and die, while the foam (46) suppresses heat loss from the hot water. The method may be carried out using a portable tool (10) which includes an air blower (14), a container (20) of a concentrate for the aqueous solution, a foam-generating tube (24) ending in an open-topped chute (26). The hot water may be provided through a flexible hose (22) from an external boiler (23), and after being used to produce the foam (46), the hot water be sprayed onto the top end of the chute (26).
