Vernonia fasciculata

RHS Plant Profile

prairie ironweed

Herbaceous Perennial

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A clump-forming perennial with upright, smooth, leafy stems to 1.2m high. Leaves are lance-shaped, toothed and deep green, and evenly spaced up the stem. In autumn, tight clusters of small violet flowers are produced on branched stems above the foliage. Flowers are followed by rusty red seedheads

Position

Full sun, Partial shade

Soil Types

Chalk, Clay, Loam, Sand

Max Height

1-1.5 metres

Max Spread

0.1-0.5 metres

Size

Time to Maturity: 2–5 years
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 Poorly–drained
pH: Acid or Alkaline or Neutral

Position

Full sun Partial shade

Aspect: East–facing or South–facing or West–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: Asteraceae
Native to GB/Ireland: No
Foliage: Deciduous
Habit: Clump forming
Genus: Vernonia are annuals, perennials, climbers, sub-shrubs, shrubs and trees, though only the perennials are in cultivation. They have upright stems, simple, stalkless leaves and flat branched heads of tubular purple or reddish pink, occasionally white, flowers
Name Status: Correct

How to Grow

Cultivation

Grow in a light, moderately fertile, moist soil preferably in full sun but will tolerate partial shade

Propagation

Propagate by seed or by division; will self seed freely if not deadheaded

Suggested planting locations and garden types

Cottage and informal garden
Prairie planting
Wildflower meadow
Flower borders and beds

Pruning

Deadhead to prolong flowering and, if necessary, to prevent self-seeding

Pests

May be susceptible to slugs and leaf miners

Diseases

Generally disease-free