Weed Information: Prohibited Noxious Weeds

Subscribe to our free E-Newsletter, "Agri-News" (formerly RTW This Week)Agri-News
This Week
 Prohibited Noxious | Noxious | Weed Information Home Page

Weeds listed in the Alberta Weed Control Act are a threat to Alberta’s environment, economy and society. They have the potential to degrade habitiats, reduce biodiversity, increase erosion, cause widlfires, reduce property value, create obstacles to international trade and cause reduction in productivity of agricultural land.

Under the Alberta Weed Control Act, Prohibited Noxious weeds need to be destroyed and Noxious weeds need to be controlled. Please refer to Legislation link for a copy of the Act and for more information.

The best method of weed control is prevention. Please familiarize yourself with these weeds to avoid introductions and minimize spread on the land you own or occupy.

Prohibited Noxious

Aquatic | Grass | Herbs/Forbs | Ornamental | Tree/Shrub


Eurasian water milfoil,
Myriophyllum spicatum
Flowering rush,
Butomus umbellatus
Iris, pale yellow,
Iris pseudacorus
Loosestrife, purple,
Lythrum salicaria

Goatgrass, jointed, Aegilops cylindrica Medusahead, Taeniatherum caput-medusaNutsedge, yellow, Cyperus esculentus

Bartsia, red,
Odontites vernus (Bellardi)
Hoary alyssum,
Berteroa incana
Knapweed, Russian,
Rhaponticum repens
Ragwort, tansy,
Jacobaea vulgaris
Cinquefoil, sulphur,
Potentilla recta
Hogweed, giant,
Heracleum mantegazzianum
Knapweed, spotted,
Centaurea stoebe ssp. micranthos
Rush skeletonweed,
Chondrilla juncea
Crupina, common,
Crupina vulgaris
Knapweed, bighead,
Centaurea macrocephala
Knapweed, squarrose,
Centaurea virgata ssp. Squarrosa
Halogeton glomeratus
Dyer's woad,
Isatis tinctoria
Knapweed, black,
Centaurea nigra
Knapweed, Tyrol,
Centaurea nigrescens
St John's-wort, common,
Hypericum perforatum
Garlic mustard ,
Alliaria petiolata
Knapweed, brown,
Centaurea jacea
Knotweed, giant,
Fallopia sachalinensis
Starthistle, yellow,
Centaurea solstitialis
Hawkweed, meadow ,
Hieracium caespitosum
Knapweed, diffuse,
Centaurea diffusa
Knotweed, hybrid Japanese,
Fallopia × bohemica
Thistle, marsh,
Cirsium palustre
Hawkweed, mouse-ear,
Hieracium pilosella
Knapweed, hybrid,
Centaurea × psammogena
Knotweed, Japanese,
Fallopia japonica
Thistle, nodding,
Carduus nutans
Hawkweed, orange,
Hieracium aurantiacum
Knapweed, meadow,
Centaurea × moncktonii
Tribulus terrestris
Thistle, plumeless,
Carduus acanthoides

Balsam, himalayan, Impatiens glandulifera

Autumn olive,
Elaeagnus umbellata
Buckthorn, common,
Rhamnus cathartica
Tamarix ramosissima
Tamarisk, smallflower,
Tamarix parviflora
Barberry, common,
Berberis vulgaris
Buckthorn, common,
Rhamnus cathartica
Tamarisk, Chinese,
Tamarix chinensis
Share via AddThis.com
For more information about the content of this document, contact Chris Neeser.
This document is maintained by Stacey Tames.
This information published to the web on August 29, 2013.
Last Reviewed/Revised on August 21, 2018.