Hexazinone is a non-selective, primarily contact herbicide, absorbed by the leaves and roots, with translocation acropetally.
 
Hexazinone Useage 
Hexazinone is a post-emergence contact herbicide effective against many annual and biennial weeds and, except for Sorghum halepense, most perennial weeds, at 6-12 kg/ha. Used for selective control in alfalfa, pineapples, sugar cane and in plantations of certain coniferous species; also on non-crop areas, but not on sites adjacent to deciduous trees or other desirable plants.
 
Hexazinone Phytotoxicity
Should not be used for weed control in larch (Larix spp.) or in areas planted with deciduous species.