Chamerion (syn Epilobium) angustifolium The tall, airy pink flowers you often see at the roadside or on waste ground, also known as 'Canadian Fireweed'. Can be a bit invasive. For the less invasive and sought after white form see 'rare plants' - (the seed of the white one is said to be sterile.)
Larval foodplant for the Elephant Hawkmoths and great nectar attractant for other moths and thus bats that eat them. Also very attractive to bees. Currently available as 3 bare root plants for 5.50. Some seed available in autumn, but it is difficult to germinate..