A salt represented by the Formula (1), wherein K represents a quaternary ammonium cation of the formula selected from the- group consisting of Formula (2), Formula (3), Formula (4), and Formula (5), wherein R represents an alkyl selected from the group consisting of tallow, soya and oleyl alkyla, and x and y in Formula (4) are integers from the range 1 to 15, inclusive, a herbicidal composition comprising such salt, and a method of combating undesirable plant vegetation using such salt. The salts are herbicidal ionic liquids.
