the purple pitcher plant ( sarracenia purpurea ) is a carnivorous plant native to north america and canada ,due to the similar climate conditions in its native range the purple pitcher plant can survive the uk climate and there is actually a few wild populations in the uk some of which were introduced in the 1960s and are still present today ,that being said ,as a non native this plant should never be released into the wild or allowed to escape from the garden , it is a bog plant growing in the margins and the edges of aquatic habitats ,the leaf structure at the top of the trap produces nectar which attracts insects that slip into the trap and drown in the fluids at the bottom providing the plant with nutrients although they arent very efficent with only around 1% of prey insects that visit the trap actually being caught by the plant so they wont decimate the insect population of your garden but are an interesting addition to a pond or bog garden.