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The Northern Latitude Plant Materials Center is open by appointments only. Please call 907-745-4469 for further information.

Invasive Plants and Agricultural Pest Management

Welcome to Alaska's Invasive Plant Program. Our program coordinates prevention, outreach and management strategies for invasive plant issues through collaboration with land managers, agencies, organizations and policy makers across Alaska. These efforts are guided by the implementation of our Strategic Plan and relevant noxious weed regulations and policies. Our goal is to help keep Alaska's pristine landscapes and natural resources free from impacts of noxious and invasive plants.

PMC Programs


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5310 S Bodenburg Spur
Palmer, AK 99645
Phone: 907-745-4469
Fax: 907-746-1568

Mon. - Fri.
8 a.m. - 4 p.m.

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Giant Hogweed (Heracleum mantegazzianum)

AK Natural Heritage Program Invasiveness Ranking: 81

First federally listed noxious weed in Alaska

  • Biology
  • Impact
  • Distribution
  • Taking Action
  • Resources

  • • Grows up to 10-15 feet tall

  • • Leaves are large, compound and dissected┬ámeasuring up to 3-5 feet wide

  • • Umbel inflorescence grows up to 2.5 feet across

  • • Flowers are small and white to light pink

  • • Stems are hollow and have dark red or purple spots and bristles

  • • It produces a watery sap that can cause severe dermal injury to humans, birds and other animals

  • **This plant closely resembles native cow parsnip but can be distinguished by larger inflorescence size, deep leave dissection and overall plant height.

giant hogweed

Giant hogweed reproduces by both seed, up to 50,000 per plant, and fragmented roots. Due to its giant size, it has the potential to form dense canopies that enable it to outcompete and displace native riparian vegetation.

The plant produces a watery sap that can cause severe blistering and burning of the skin, impacting human health and negatively impacting environmental resources.

In Alaska, there has only been one documented occurrence of giant hogweed. This infestation site was in Kake and has been successfully eradicated, and continually monitored.

Habitat: Riparian areas, river banks, streams, roadsides, gardens, and waste areas

  • • If you think you have seen giant hogweed, report the site by calling 1-877-INVASIV.

  • • Manual control must be taken with caution because of the toxic watery sap, the giant hogweed produces. Always wear protective equipment when handling this plant.

  • • Manually remove by cutting roots at least 3-4 inches below the surface.

  • • Mowing repeatedly will also control this plant.

  • • Systemic herbicides may also be effective.


1-877-INVASIV (468-2748)
Invasive Weeds and Agricultural Pest Coordinator