The brimstone is one of the longest-lived UK butterflies, surviving as an adult for nearly a year. Its welfare depends on buckthorn and alder buckthorn shrubs in hedgerows, woodland edges and scrub.
Brimstone welfare spans a year-long adult lifespan that requires multiple habitat features. Summer breeding habitat requires mature buckthorn or alder buckthorn shrubs — these slow-growing shrubs are often removed from hedgerows as they are thorny and difficult to manage. Winter hibernation in dense evergreen cover (ivy, holly) requires undisturbed vegetation that is rarely provided in tidily managed gardens. Spring nectar sources (bluebells, dandelions, primroses) fuel the emergence from hibernation. Gardens and hedgerows that retain all three elements — foodplant shrubs, evergreen hibernation cover and spring nectar plants — can support brimstone breeding and overwintering.