Nepeta x faasenii. Catmint. This plant is a real winner. 'Walkers Low' is my personal favourite, although 'Six Hills Giant' is another top performer. The grey-green foliage sets off sprays of lavender-blue flowers starting in early summer. Cut it back when it starts to get tired looking in late July and it will rebloom through the fall. Plant it in full sun, in well-drained soil. Use as a companion plant in a perennial border, or as a large groundcover in open areas.