A vigorous fast growing ground cover, this perennial is ideal for a well drained hot dry bank or rockery. It has narrow silvery grey leaves, and masses of star shaped white flowers borne in loose heads in late spring and summer. It is particularly attractive when used as an underplanting against a darker background.  The foliage is dense and an effective weed suppressant. It grows to 15cm in height and will spread up to 1metre.  Very cold hardy.