Callitriche hermaphroditica

RHS Plant Profile
autumnal water starwort

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Other common names

brigwlyyd cynhaeaf, star grass, water starwort

Synonyms

Callitriche autumnalis

Bogs Herbaceous Perennial

A submerged aquatic perennial with slender stems bearing linear leaves. Useful as an oxygenating plant for ponds and aquaria

Position

Full sun, Partial shade

Soil Types

Loam

Max Height

Up to 10 cm

Max Spread

0.5-1 metres

Size

Time to Maturity
2–5 years
Max Spread
0.5-1 metres
Max Height
Up to 10 cm

Growing Conditions

Loam
Moisture
Poorly–drained
pH
Acid or Alkaline or Neutral

Position

Full sun Partial shade
Aspect
South–facing or West–facing or East–facing
Exposure
Exposed or Sheltered
Hardiness

Hardiness Ratings

All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets

  • H1A: under glass all year (>15C)
  • H1B: can be grown outside in the summer (10 - 15)
  • H1C: can be grown outside in the summer (5 - 10)
  • H2: tolerant of low temperatures, but not surviving being frozen (1 to 5)
  • H3: hardy in coastal and relatively mild parts of the UK (-5 to 1)
  • H4: hardy through most of the UK (-10 to -5)
  • H5: hardy in most places throughout the UK even in severe winters (-15 to -10)
  • H6: hardy in all of UK and northern Europe (-20 to -15)
  • H7: hardy in the severest European continental climates (< -20)
H7

Colour & Scent

Season Stem Flower Foliage Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family
Plantaginaceae
Native to GB/Ireland
Yes
Foliage
Deciduous
Habit
Submerged
Genus
Callitriche can be terrestrial or aquatic perennials with slender stems bearing linear or spoon-shaped leaves and minute flowers in summer, useful oxygenating plants for ponds
Name Status
Correct
Plant Range
N America, Europe

How to Grow

Cultivation

Grow in baskets to restrict spread, in a peat-free, loam-based potting compost in full sun or partial shade. Submerge baskets in water 45-60cm deep

Propagation

Propagate by softwood cuttings of terminal shoots

Pruning

No pruning required. Cut back after flowering

Pests

Generally pest-free

Diseases

Generally disease-free