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Butomus umbellatus

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© RHS 2002

Characteristics

Plant type

Aquatic or Bog

Habit

Submerged

Resilience

Hardiness

old H4 (hardy)

Colour

Flower

Pink in Summer

Foliage

Green in Autumn, Spring and Summer

Size

Ultimate height

1-1.5 metres

Ultimate spread

0.1-0.5 metres

Time to ultimate height

5-10 years


Preferred common name

flowering rush

Family

Butomaceae


Butomus are submerged rhizomatous perennials with narrowly strap-shaped leaves and 6-petalled pink flowers held in umbels well above water level

B. umbellatus is an herbaceous perennial to 1.2m, with upright, twisted grassy leaves and stiff stems bearing umbels of fragrant rosy-pink flowers 2cm in width in late summer

Other common names

  • grassy rush
  • lily grass
  • water gladiolus

How to grow

Sunlight

  • Full sun

Aspect

  • South-facing or West-facing
  • Sheltered or Exposed

Cultivation

Grow in fertile mud at pond margins or in water up to 25cm deep, in full sun

Soil

  • Poorly-drained
  • Neutral, Acid or Alkaline
  • Sand, Clay or Loam

Propagation

Propagate by seed sown as soon as ripe or by rhizome division in spring

Suggested planting locations and garden types

Cottage/Informal Garden or Wildlife Gardens


How to care

Pruning

Cut back after flowering

Pests

Can get water lily aphid

Diseases

Generally disease free