Agapanthus africanus is a clump-forming evergreen perennial which is half-hardy. It has deep blue, trumpet-shaped flowers in umbels on tall stems which appear in late summer over mid green linear leaves. Grow in fertile, moist, but well-drained soil in full sun. In all but the mildest areas, should be overwintered under cover.
Don’t forget that this plant will benefit from having its roots restricted to encourage flowering.