Viper is an invigorating sativa that was bred from an indigenous Burmese landrace and a native Mexican strain known as Blackseed. First cultivated by Reeferman Seeds, Viper inherits buzzing, cerebrally-targeted effects and a spicy, citrus aroma. In a show of its nearly pure sativa genetics, Viper grows tall and bears fluffy buds that finish their flowering cycle in about 10 weeks.