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

• Position: full sun or partial shade
• Soil: moderately fertile, well-drained
• Rate of growth: fast
• Flowering period: June to July
• Hardiness: fully hardy
  
  Stunning lagoon blue flowers, each with a white fleck, appear in upright columns from early summer. 'Persian Slipper' looks fabulous when woven through mixed or herbaceous borders, where it will add height. The flowering spires have a spicy, peppery scent and look fabulous when planted with purple and pink flowering early summer perennials such as Geranium and Astrantia.
  
  
• Garden care: Stake with bamboo canes in spring before the flowers appear and deadhead the faded blooms to encourage a second flush of flowers. Protect young plants from slug and snail attack.