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
- PMC Home Page
- Horticulture
- Industrial Hemp
- Invasive Plants
- Plant Pathology
- Potatoes
- Potato Program
- Certified Seed Potato Production
- Disease Risk Monitoring
- Publications and Reports
- Late Blight Management Plan for Alaska, 2005
- 2017 AK Potato Seed Certification Handbook
- 2018 AK Certified Seed Potato Growers
- 2018 Potato Postharvest Processing Evaluation Report
- Potato Variety Trial Project 2013
- 2015 Field Potato Evaluation
- 2016 Potato Germplasm Winter Growout
- Download .zip video of 2014 Potato Symposium Meeting
- Resources
- Revegetation
- Seed Production
- Soil Conservation
- Publication List
- Native Plant Source Directory
- PMC Staff Directory
- PMC Weather Station

5310 S Bodenburg Spur
Palmer, AK 99645
Phone: 907-745-4469
Fax: 907-746-1568
Mon. - Fri.
8 a.m. - 4 p.m.
Click Map For Directions
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Spotted Knapweed (Centaurea stoebe)
AK Natural Heritage Program Invasiveness Ranking: 86
A native to Europe and Asia, the spotted knapweed has become a serious problem in pastures and rangelands of the western lower 48.
- Biology
- Impact
- Distribution
- Taking Action
- Resources
- • Biennial to short-lived perennial
- • Rosette leaves are deeply divided while stem leaves are alternate and are increasingly smaller toward the top
- • Stems are extensively branched
- • Flowers are urn-shaped, solitary at the end of each branch and purplish-pink
- • Flowers grow up to 1 inch wide and are composed of purple, disc-like florets
- • The dark comb-like fringe on the tip of the bracts, just below the flower petals, give the flower a &quo;spotted&quo; appearance
- **Spotted knapweed can be confused with Alaska's native diffuse knapweed (C. diffusa). The native diffuse knapweed has spine-tipped bracts, not comb-like tips on its bracts.
