Blueweed


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Pest Information
Common Name: Blueweed
Family Name: Boraginaceae
Latin Name: Echium vulgare L.
Other Names: Blue Devil, Viper's Bugloss, Blue-thistle, Snake flower
Provincial Designation: Noxious
Life Cycle: Biennial
Mode of Spread: Seed, Vegetative

Detailed Information
Provincial Situation: Blueweed is found in every province in Canada but is considered sparse in Alberta. High densities can be found in the southwestern part of the province
Key Characteristics:
  • Blue funnel-shaped flowers (white/pink/purple in development)
  • Bristly hairs throughout plant on leaves and stems
  • Basal rosette has long lance-shaped leaves
  • Hairs have swollen bases, dark spots on stem
  • Bright pink/red stamens, four long one short, extending beyond petals
Similar Species: Borage Borago officinalis cup-shaped flowers and flower stalks of borage are longer than sepals. Grown as crop in AB href="http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/crop748?opendocument" mce_href="http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/crop748?opendocument"> Hound’s-tongueCynoglossum officinale reddish-purple flowers with no spots on stems. Noxious status in AB. href="http://www.invasiveplants.ab.ca/Downloads/FS-HoundsTongue.pdf" mce_href="http://www.invasiveplants.ab.ca/Downloads/FS-HoundsTongue.pdf"> Salvation janeEchium plantagineum- has 2 stamens projecting past flower tube (as opposed to 4 in Blueweed). Not known to be in AB. href="http://www.dpi.vic.gov.au/dpi/vro/vrosite.nsf/pages/weeds_herbs_annual_patersons_curse" mce_href="http://www.dpi.vic.gov.au/dpi/vro/vrosite.nsf/pages/weeds_herbs_annual_patersons_curse">
Growth and Development (Life Cycle): Biennial, occasionally annual, sometimes a short lived perennial.
Where it Grows (Habitat & Ecology): Blueweed is usually not found in cultivated crops, but can occur in rangelands, pastures, roadsides, urban areas and along water courses. Prefers moist climates, but is also relatively drought tolerant due to a fleshy taproot which can exceed 1 m in depth. Requires vernalization for flowering to occur.
How it Spreads (Mode of Spread): Blueweed produces up to 2800 seeds/plant, which can remain viable in the soil for up to 10 years and germinate from a maximum of 3 cm deep. Seed viability is reduced in moist climates. Seeds can be easily transported by sticking to clothing, animal fur, etc., or transported by water due to their ability to float. Blueweed is insect pollinated. Germination occurs between 17 and 32 C with adequate precipitation. Variable hardness of seed coats contributes to sporadic germination throughout the summer.
Reproduction (Dispersal): Seeds are generally dropped in the immediate vicinity of the parent plant but may be spread by wind, animals or water.  Wind dispersal is not as much of a concern as the seeds generally land within 5 m of the parent plant.  Seeds are covered with small hairs that readily stick to animal fur, hair and clothing for transport.  Seeds may also spread by movement with water due to their ability to float.
Economic Importance (Beneficial Aspects): Blueweed is used as an herbal remedy for a variety of ailments, as a garden plant, as a source of nectar for honey, as a source of dye and insecticides.
Toxicity and Other Concerns: Contact with stiff hairs on the mature plant can cause severe physical irritation to the skin. Blueweed can also be an alternate host for fungal pathogens, and contain alkaloids, which may be detrimental to livestock and humans. Reduces biodiversity of fauna and flora and is not utilized by wildlife or domestic animals. In sheep pastures it can cause the wool to become matted. Blueweed seeds can contaminate crop seeds, especially clover.
Origin: Native to Southern Europe and was first reported in Canada in 1862.
Seed Production: Blueweed is insect pollinated and can produce up to 2800 seeds (called nutlets) per plant.  The seeds can remain viable in the soil for up to 10 years and germinate from a maximum depth of 3 cm.  Seed viability is reduced in dry climates. Germination occurs between 17 and 32 C and may occur any time throughout the growing season; adequate moisture is required for germination.
How to Control:

Integrated weed management (IWM) considers the overall management of a weed species with the objective of preventing the establishment of the weed from ever occurring, to prevent the spread or to minimize the impact.  IWM relies on the combination of a variety of methods such as chemical, biological, mechanical, and cultural controls as well as overall preventative measures.  Using IWM creates an opportunity to use herbicides more selectively, which reduces the impact on the environment as well as slow the development of weed resistance to herbicides.

Preventative
Small infestations can be managed by hand-pulling if the root is completely removed.

Competition
Vigorous grass stands that provide good competition will help control blueweed and also make an invasion unlikely.

Fertility
Fertilizer will enhance the growth of blueweed more than grass and therefore is not recommended as a control option.  (Blueweed tends to thrive in well-drained infertile soil, while fertile soil tends to inhibit flower production.)

Cultivation
Established blueweed plants are killed if tillage cuts below the crown (Muenscher, 1946).  Repeated tillage can also deplete the seed bank as it promotes germination.

Mowing
Mowing before flowering prevents seed set.  If mowing occurs only once or is inadequate, damaged plants often produce several secondary shoots or adopt a prostrate growth habit, allowing subsequent flowering and seed set.  Mowing should be done several times during the growing season to be most effective (Klemow et al., 2002) as repeated defoliation will eventually deplete the root reserves and reduce the plant’s ability to flower and set seed.

Grazing
No published reports refer to grazing of blueweed by mammals, as coarse hairs on the weed deter grazing.  Blueweed may contain toxic metabolites so grazing is not advisable.  In general, overgrazing of pastures will allow blueweed to become established and therefore it is important to manage grazing animals to maintain perennial plant communities.

Biocontrol
No commercially available biocontrol agents available in Canada.  A Paleoarctic lace bug has been reported to feed on several plants from the Borage family including blueweed.  Two fungi (Ophiobolus spp.) have been reported on blueweed in Ontario.  Use of biological control may be limited due to the concern regarding potential damage to closely related species within the Borage family.

Prevention: Do not allow blueweed to enter onto your site; use weed free hay, fill dirt and seed.  At infested sites, remove plant seeds from personal gear, equipment and vehicles before leaving the site.  Blueweed is generally not a problem in areas with dense vegetative cover, so minimize soil disturbances and promptly re-vegetate disturbed areas.  Maintain healthy pastures – do not allow them to become overgrazed.
Cultural Control: Hand pulling for small infestations can be effective, if the root is completely removed. Handling blueweed is comparable to handling fiberglass; the stiff hairs are painful to touch, so be sure to wear gloves and long-sleeved shirts when handling this plant. For mature blueweed control, in small areas; dig, bag and burn.
Competition: Vigorous grass stands that provide good competition will help control blueweed and also make an invasion unlikely.
Fertility: Fertilizer will enhance the growth of blueweed more than grass and therefore is not recommended as a control option.  Blueweed tends to thrive in well-drained infertile soil, while fertile soil tends to inhibit flower production.
Cultivation: Established blueweed plants are killed if tillage cuts below the crown.  Repeated tillage can also deplete the seed bank as it promotes germination.
Mowing: Mowing before flowering prevents seed set.  If mowing occurs only once or is inadequate, damaged plants often produce several secondary shoots or adopt a prostrate growth habit, allowing subsequent flowering and seed set.  Mowing should be done several times during the growing season to be most effective as repeated defoliation will eventually deplete the root reserves and reduce the plant’s ability to flower and set seed.
Grazing: No published reports refer to grazing of blueweed by mammals, as coarse hairs on the weed deter grazing.  Blueweed may contain toxic metabolites so grazing is not advisable.  In general, overgrazing of pastures will allow blueweed to become established and therefore it is important to manage grazing animals to maintain perennial plant communities.
Fire: No information available.
Bio-Control: No commercially available bio-control agents available in Canada.  A Paleoarctic lace bug has been reported to feed on several plants from the Borage family including blueweed.  Two fungi (Ophiobolus spp.) have been reported on blueweed in Ontario.  Use of biological control may be limited due to the concern regarding potential damage to closely related species within the Borage family.
Other Canadian Links: British Columbia Government href="http://www.agf.gov.bc.ca/cropprot/weedguid/blueweed.htm" mce_href="http://www.agf.gov.bc.ca/cropprot/weedguid/blueweed.htm"> href="http://www.agf.gov.bc.ca/weedsbc/weed_desc/blueweed.html" mce_href="http://www.agf.gov.bc.ca/weedsbc/weed_desc/blueweed.html" Ontario Government

 

Government of Canada Poisonous Plant Website href="http://www.cbif.gc.ca/pls/pp/ppack.info?p_psn=101&p_type=all&p_sci=comm&p_x=px" mce_href="http://www.cbif.gc.ca/pls/pp/ppack.info?p_psn=101&p_type=all&p_sci=comm&p_x=px"> Alberta Invasive Plant Council

 

Invasive Plant Council of BC href="http://www.invasiveplantcouncilbc.ca/invasive-plants/blueweed" mce_href="http://www.invasiveplantcouncilbc.ca/invasive-plants/blueweed">
Herbarium Collections:
  1. University of Alberta Vascular Plant Herbarium -  1 specimen from 1999, collector Marc McPherson from Lundbreck Falls, AB


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Last Modified: 2011-11-29 16:08:40.312

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