Alligator weed (Alternanthera philoxeroides (Mart.) Griseb.) has been spread all over the India, especially in tropical and warm temperate regions. Recently, its occurrence was recorded in tropical parts and foot hills of Uttarakhand state. The uphill journey of the alligator weed in the state is a serious matter of concern. The weed may reach to alpine region of Himalaya soon by taking route along water courses, as it can readily survive in cold winter and severe frost.