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Herbaceous Perennial

Vernonia 'Summer's Swan Song'

ironweed 'Summer's Swan Song'

A dense, clump-forming perennial to 75cm tall with stout, upright, self-supporting stems densely clothed with narrow, lance-shaped olive-green leaves. Dense clusters of large dark, rich purple flowers appear from late summer to autumn

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Ultimate height

0.5–1 metres

Time to ultimate height

2–5 years

Ultimate spread

0.1–0.5 metres

Chalk

Clay

Loam

Sand

Moisture

Moist but well–drained

pH

Acid, Alkaline, Neutral

	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Full sun
Partial shade

Aspect

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)

Botanical details

Family: Asteraceae
Native to GB / Ireland: No
Foliage: Deciduous
Habit: Clump forming, Columnar upright
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: Accepted

How to grow

Cultivation

Grow in any light, moist soil in full sun or partial shade

Propagation

Propagate by seed or division

Suggested planting locations and garden types

Cottage and informal garden
Prairie planting
Flower borders and beds

Pruning

Deadhead regularly to prolong flowering

Pests

May be susceptible to slugs

Diseases

Generally disease-free

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