These mat forming plants produce 12 inch tall, somewhat lax stems. The spike-like stems are covered with bright sky blue flowers. The stems have many branches and make a nice display of flowers over many weeks in summer. After blooming, cut back hard to produce an attractive mound of low growing bushy foliage. Starts off as a bushy upright perennial, as plants age they become a slowly spreading mat with many small leaves that produced a number of thin, wiry, stems with many flowers. 'Royal Blue' has a nice bright blue color that stands out in the garden and mixes well other low growing perennials. Grow in an area with good soil that drains freely but is not overly dry in full sun to light shade. Plants will bloom the first year.
Cover the seeds very thinly with soil medium, best to surface sow and then sprinkle some soil medium over them; use70F with germination in 2 to 3 weeks. Plants grow fast and they can be planted out after a few weeks of growth. The species is native from Europe were it prefers calcareous soils.