An agricultural co-formulation comprising: an effective amount of at least one plant growth regulator, or at least one plant growth regulator and an additional biologically active ingredient, in a comminuted form having an average particle size in the range of from 1 to 12 microns; at least one oil; at least one oil-soluble surfactant dispersing agent; and at least one emulsifying agent, wherein the final concentration of the at least one plant growth regulator, or at least one plant growth regulator and an additional biologically active ingredient, is optionally adjusted by adding additional oil and one or more rheology modifiers and/or activation agents as required to substantially stabilise the co-formulation; and wherein the efficacy of the plant growth regulator is substantially maintained or improved; and one or more methods of making the co-formulation.