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

• Position: full sun
• Soil: well-drained, fertile soil
• Rate of growth: average
• Flowering period: July to October
• Hardiness: hardy (borderline)
  
  A cool white-flowering hyssop, that produces its slender bottlebrush-like spikes for several months from midsummer. These not only look great (and will help add vertical interest to the border), but they are also sought after by pollinating insects. The subsequent seedheads are a feast for birds.
  
  
• Garden care: Don't cut back the faded flower-stems until early spring, as they provide interest in the winter months. Lift and divide congested colonies in spring.