Chamaenerion angustifolium

RHS Plant Profile

rosebay willowherb

Other common names

bay willow, blooming willow, burntweed, fireweed, French willow, French willowherb, great willowherb, herb wickopy, moose tongue, Persian willow, pigweed, purple rocket, rose bay, rose elder, wickup

Synonyms

Epilobium angustifolium
Epilobium spicatum
Chamerion angustifolium

Herbaceous Perennial

A rhizomatous, strongly-spreading perennial to about 1.5m tall, forming dense colonies, with long, narrow, willow-like leaves arranged spirally up the pink-tinged stems. Striking spikes of purplish-pink flowers bloom from summer to autumn, followed by long pink-tinged seed pods; seeds are cocooned in silky plumes

Position

Full sun

Soil Types

Chalk, Clay, Loam, Sand

Max Height

1-1.5 metres

Max Spread

1.5-2.5 metres

Size

Time to Maturity: 2–5 years
Max Spread: 1.5-2.5 metres
Max Height: 1-1.5 metres

Growing Conditions

Chalk Clay Loam Sand

Moisture: Moist but well–drained or Poorly–drained or Well–drained
pH: Acid or Alkaline or Neutral

Position

Full sun

Aspect: West–facing or East–facing or South–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: Onagraceae
Native to GB/Ireland: Yes
Foliage: Deciduous
Habit: Columnar upright
Genus: Chamaenerion can be annuals or perennials, sometimes invasive, with erect stems bearing willowy leaves and showy, 4-petalled flowers in terminal racemes
Name Status: Correct
Plant Range: N Hemisphere

How to Grow

Cultivation

Naturally occurs on a wide range of soils in open places such as verges or waste ground. A colourful native wildflower, with wildlife benefits, but spreads easily so may need controlling in some areas. See willowherbs for more information

Propagation

Propagate by seed or propagate by division in spring or autumn

Suggested planting locations and garden types

Wildlife gardens
Wildflower meadow

Pruning

No pruning required, though deadheading will reduce self-seeding

Pests

Generally pest-free

Diseases

Generally disease-free