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: moist, fertile, humus-rich soil
• Rate of growth: fast-growing
• Flowering period: July to August
• Hardiness: fully hardy
  
  A chance discovery by Rosy Hardy in 2015 and recently introduced. Ruffled semi-double ‘Frilly Knickers’ is a stunning sport of 'Dreaming Swan'. The large purple buds of this clump-forming perennial open to a mass of white petals with delicate hints of lilac and a boss of golden-yellow stamens. Well suited to the small garden with a long flowering season and perfect for pots!
  
  
• Garden care: Cut back the flower stems after the blooms have faded. Remove any degraded foliage in March and mulch with well-conditioned organic matter. Once established, lift and divide congested clumps in early spring.