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Herbaceous Perennial

Vernonia baldwinii

western ironweed

A clump-forming, rhizomatous perennial to 1.5m tall bearing flattened flower heads up to 30cm in diameter made up of 15-30 tiny purple flowers borne on stout, hairy stems from summer into autumn. The lance-shaped, deep green leaves have serrated margins and reach up to 17cm in length.

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Ultimate height

1–1.5 metres

Time to ultimate height

2–5 years

Ultimate spread

0.5–1 metres

Chalk

Clay

Loam

Sand

Moisture

Moist but well–drained, Well–drained

pH

Acid, Alkaline, Neutral

	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

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)

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: Correct
Plant range: C & S USA

How to grow

Cultivation

Grow in a moist, light 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
Cut flowers
Flower borders and beds

Pruning

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

Pests

Generally pest-free

Diseases

Generally disease-free

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