Chamerion angustifolium

Fireweed

Chamerion angustifolium, Fireweed, Photo © by Earl J.S. Rook
Fireweed
Photo © by Earl J.S. Rook

Flora, fauna, earth, and sky...
The natural history of the northwoods


Name:

  • Chamerion, from ???
  • angustifolium, from the Latin, "narrow leaved"
  • Fireweed, because it is one of the first plants to spring up after fire.
  • Other common names include: Common Fireweed, Perennial Fireweed, Narrow Leaved Fireweed, Great Willow Herb, Rosebay, Rosebay Willow Herb, Blooming Sally, Blood Vine, Bloomi (UK), mjölke, mjölkört, rallarros, brudfackla, duntrav, kropp, praktduna, rävrumpa, rävsvans, skogsbloss (Swe),Geitrams (Nor), Gederams (Dan), Maitohorsma (Fin), Sigurskúfur (Isl), Schmalblättriges Weidenröschen, Stauden-Feurkraut (Ger), Bastaardwederik, Wilgeroosje (NL), Wierzbowka kiprzyca (Pol), Epilobe à feuilles étroites, Epilobe (Fr), Erba di Sant' Antonio, Epilobe, Garofanino maggiore (It)

Taxonomy:

  • Kingdom Plantae, the Plants
    • Division Magnoliophyta, the Angiosperms (flowering plants)
      • Class Magnoliopsida, the Dicotyledons
      • Subclass Rosidae
        • Order Myrtales
          • Family Onagraceae, the Primroses
            • Genus Chamerion, the Fireweeds
  • Taxonomic Serial Number: 566020
  • Also known as Chamaenerion angustifolium, Chamerion danielsii, Chamerion platyphyllum, Epilobium angustifolium

Description:

  • Robust native perennial herb.
  • Leaves alternate, narrow, lance shaped, 3"-6" long.
  • Stem single, 3'-9' tall, and may be very leafy.
  • Roots fine, with rhizomes extending down to 18", most to 6".
  • Flowers rose pink, 15 or more in spike at top of stem.
    • Sepals 4
    • Petals 4
    • Stamens 8, inner 4 shorter than outer 4
    • Ovary 4 chambered
  • Fruit a capsule with 300-500 seeds.
  • Seed have a tuft of long hairs on one end.

Identification:

  • Unmistakable in bloom; nothing else like it in the North Country.
  • Field Marks
    • upright growth habit
    • rose pink flowers in prominent spike at tip of stem

Distribution:

  • Circumboreal; in all of the Canadian provinces and throughout the United States except in the southeastern states and Texas.

Habitat:

  • Disturbed ground such as cut-over or burned forests and swamps, avalanche areas, recently deglaciated areas, and riverbars. Additional disturbed sites are highway and railroad rights-of-way, waste places, and old fields.
  • Abundant in coniferous forest, mixed forest, aspen parkland, grasslands, and muskeg.
  • Declines due to the effects of competing vegetation. Progressive changes from open to closed canopy in a forest result in decreasing abundance.
  • An important colonizer following vegetation disturbances in temperate climates worldwide.
  • Low resistance to human trampling.

Fire:

  • Adapted to fire through rhizomes and prolific production of wind dispersed seed. Depending upon depth of rhizomes in the soil, fireweed is moderately susceptibile to resistant to fire. The majority of roots and rhizomes are in the top 2" of mineral soil and can survive relatively intense fires.
  • An important off-site colonizer after fire.

Associates:

History:

  • Floral emblem of the Yukon Territory.

Uses:

  • Bees produce a delicious honey from the flowers.

Reproduction:

  • Reproduces by seed and vegetatively by rhizomes
  • Flowers rose pink.
  • Fruit narrow, red or green seed pods that split and release a multitude of tiny, fluffy, white seeds.
  • Seed dispersal by wind.
  • Airborne seeds allow fireweed to establish rapidly.
  • Requires bare mineral soil in addition to high light for germination. Moisture supply is more stable and more nutrients are available on a mineral soil seedbed.
  • Once established, forms large colonies via rhizomes and produces large amounts of seed.
  • Vegetative reproduction more prevalent than sexual reproduction.
  • Sprouts from rhizomes following disturbance. Shoots sprouting from rhizomes are capable of very rapid growth; they may bloom within 1 month. Fragmentation of rhizomes stimulates shoot production. Rhizome length depends on soil fertility and amount of competing vegetation present.
  • Sexual Reproduction: Can self-cross or outcross. Principally pollinated by insects. A prolific seed producer, one plant may produce about 80,000 seeds per year.
  • One of the most abundant colonizers on Mount St. Helens.
  • Seeds are nondormant and germinate over a variety of temperatures. Most newly collected seeds germinate within 10 days. Fireweed does not create a long-lived seedbank; most seeds lose viability after 18-24 months. Optimum germinating conditions are warm, well-lighted, and humid.
  • Seed hairs or plumes respond to humidity. Increased humidity causes a decreased plume diameter which results in reduced loft. This increases the chance that seeds are deposited in places with moisture adequate for germination. Plumed seed has low rates (0.21 to 0.23 foot per second ) of fall in still air.
  • Phenology:
    • Root growth begins at 40 degrees F, preceeding stem emergence.
    • Shoots emerge in spring.
    • Leaves are full grown approximately 1 month after emergence.
    • Flowers bloom June-September.
    • Fruits mature approximately 1 month later.
    • Seeds are released beginning in August and continue to be shed after shoots have died from frost injury.
    • Foliage will turn color with limited water availability in the late summer and fall.
    • Seeds germinate late summer or fall, and seedlings overwinter as a rosette. The primary and secondary roots of seedlings may develop buds which overwinter. Shoot buds form in the fall on lateral roots and overwinter just below the soil surface
  • Fireweed production may vary with severity of fire. Severe fires remove organic soil layers, exposing mineral soil which is an excellent seedbed for fireweed. Therefore, cover and density are greatest on severely burned areas because of good seedling establishment.

Propagation:

  • By seed,
  • Planting rhizomes may speed colonization of a disturbed area. Fireweed plants established best with the addition of fertilizer.

Cultivation:

  • Hardy to USDA Zone 2 (average minimum annual temperature -50ºF)
  • Cultural Requirements
    • Full sun
    • Ordinary garden soil
  • Grown as an ornamental; however, it can become an aggressive weed.
  • Available by mail order from specialty suppliers.

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Last Updated on 14 October, 2002