Sonchus asper

RHS Plant Profile
prickly sowthistle

Save a plant

Where do you want to save Sonchus asper?

Plants I own
Wishlist
Go to My Plants
prickly sowthistle RHS
prickly sowthistle RHS

Synonyms

Sonchus oleraceus var. asper

Annual Biennial

A robust annual, up to 1.5m tall, with shiny, deeply lobed leaves with soft prickles, a hollow stem with milky sap, and, in summer, clusters of small, dandelion-like flowers followed by short-lived, fluffy seedheads

Position

Full sun

Soil Types

Chalk, Clay, Loam, Sand

Max Height

1-1.5 metres

Max Spread

0.1-0.5 metres

Size

Time to Maturity
1 year
Max Spread
0.1-0.5 metres
Max Height
1-1.5 metres

Growing Conditions

Chalk Clay Loam Sand
Moisture
Moist but well–drained or Well–drained
pH
Acid or Alkaline or Neutral

Position

Full sun
Aspect
South–facing or West–facing
Exposure
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
Asteraceae
Native to GB/Ireland
Yes
Foliage
Deciduous
Habit
Clump forming
Genus
Sonchus are mostly annuals with a few perennials and rarely a shrub. Most produce a basal rosette of deeply-toothed leaves, upright stems with clasping leaves and yellow, dandelion-like flowers
Name Status
Correct

How to Grow

Cultivation

Grows naturally in cultivated ground, waste ground, roadsides and other open areas; a common garden weed

Propagation

Spreads readily by seed

Suggested planting locations and garden types

  • Wildflower meadow
  • Wildlife gardens

Pruning

No pruning required

Pests

May be susceptible to aphids and a leaf miner

Diseases

May be susceptible to powdery mildews and a leaf spot