This is a lovely, white flowering, hardy herbaceous that dies back in the winter and comes back again the following spring.  Flowers for most of the summer if dead headed.  Ours have been raised from seed, so there is a little variation in the flower, some are single daisy like white flowers with pale cream centre, others have double flowers that are more like little pompoms.  This is a great cut flower either fresh or dried, and is loved by bees and pollinators.