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: reliably moist, or aquatic compost
• Depth of water: 0-8cm
• Rate of growth: fast-growing
• Flowering period: July to August
• Hardiness: fully hardy
  
  Mentha aquatica is a native watermint, that will quickly spread to form attractive, aromatic groundcover around the margins of a pond (or other reliably moist and boggy areas). The fluffy-looking clusters of lavender flowers that top reddish-purple stems in July and August, are sought-after by bees and other pollinators, which makes it ideal for wildlife-friendly gardens.
  
  
• Garden care: In smaller areas, or to help prevent it overcrowding its neighbours, pot it up in an aquatic planting basket lined with hessian. Then, before planting out, apply a 2.5cm (1in) top-dressing of pea shingle or gravel to prevent the compost from getting washed away or clouding the water. Every so often during the growing season, trim back any stems that are beginning to encroach on smaller, less vigorous plants nearby.