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Perennial RHS Award of Garden Merit

Hardy Geranium

Geranium 'Rozanne'

Hardy Geranium (Geranium 'Rozanne') growing in a UK garden

An outstanding, long-flowering perennial producing saucer-shaped violet-blue flowers with white centres from June until the first frosts. 'Rozanne' is widely considered the finest hardy geranium ever bred, winning RHS Plant of the Centenary in 2013. It forms a low, spreading mound of deeply cut foliage that makes excellent ground cover in UK gardens.

How to grow hardy geranium

Plant in spring or autumn in any reasonable garden soil. 'Rozanne' is remarkably adaptable, thriving in sun or partial shade and tolerating clay, sand, or chalky conditions. Space plants 60 cm apart to allow the spreading habit to fill gaps naturally. Water regularly during the first season, though established plants cope well with dry spells. A light mulch of garden compost in spring provides all the feeding needed. This variety scrambles happily through other plants and over low walls, producing flowers non-stop for five months or more. It rarely needs dividing but can be split in spring if the clump becomes too large.

Pruning

No regular pruning required. If the plant becomes straggly in midsummer, cut it back hard to 10 cm above ground level — fresh growth and new flowers appear within three weeks. Cut all growth to ground level in late autumn once the foliage has died back.

Propagation

  • Division in spring
  • Basal cuttings in spring

Common problems

  • Vine weevil larvae attacking roots in containers
  • Slugs on young spring growth
  • Downy mildew in wet summers

Good companions

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