This perennial dies back to below ground level each year in autumn, then fresh new growth appears again in spring.

• Position: full sun
• Soil: light, moderately fertile, humus-rich, moist but well-drained soil
• Rate of growth: average
• Flowering period: June to October
• Hardiness: fully hardy
  
  Above the compact mound of aromatic, grey-green foliage, purple-black stems arise from early summer bearing rich, violet-blue flowers. A vibrant and long-flowering addition to the border, they look spectacular when planted with rich plums and pinks as well as smokey purples.
  
  
• Garden care: To prolong flowering remove the flower spikes as soon as they start to fade. Apply a generous 5-7cm (2-3in) mulch of well-rotted garden compost or manure around the base of the plant in spring.