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All Species

Orange Hawkweed

Hieracium aurantiacum
UAF Cooperative Extension, University of Alaska - Fairbanks, Bugwood.org

Why is it a problem?

  • Aggressive invader of lawns, meadows, wetlands and forests; forms dense vegetative mats that choke out native plants and threatens fish & wildlife habitat
  • Reproduces by seeds, underground rhizomes, and above-ground runners and stems
  • Releases toxins that inhibit growth of native plants (allopathic)
  • Produces 600 seeds per plant that remain viable in the soil for up to 7 years
  • Dispersed by wind and wildlife, and on clothing and equipment

How do I manage this plant?

  • Bright orange flowers are easily spotted when flowering in mid-summer; Remove plants as soon as they are seen, as smaller patches are much easier to control than large ones; Mark the area where plants were removed so you can revisit the site and find stems when not flowering; Chemical treatments are ineffective at this time
  • To remove a single stem, dig a hole one foot around and below the plant; Place plant and soil in a trash bag for landfill disposal
  • For small patches, smother with landscape fabric, extending the fabric a few feet beyond the edge of the patch; Leave in place for three years, monitor the perimeter, and dig or apply herbicide to any stem that pops up beyond the fabric
  • To limit seed production, collect flowers before they set seed and place in a trash bag for landfill disposal

 

More info on species biology