Dahlia are tuberous rooted perennials with pinnately divided leaves and showy flower-heads, double in many cultivars, in summer and autumn
Collerette-flowered dahlias have a single outer row of flat ray florets, with an inner ring of shorter florets surrounding the central disk florets
'Clair de Lune' grows to 1m in height, with dark, divided foliage and broad, light to creamy-yellow outer florets, cream inner ones and a deep yellow disk