Growing to 120 cm tall by 30 cm wide, it is a woody-based erect herbaceous perennial, with oval leaves and dense cushions of violet-purple flowers in summer. The specific epithet caeruleum means "dark blue". In temperate climates this plant is usually grown as a half-hardy annual for summer bedding schemes or planters. It has gained the Royal Horticultural Society's Award of Garden Merit. There are many cultivars with a variety of flower colours, including white, red, pink, and dark purple.
This post is part of the Floral Friday Fotos meme.