Prohibited noxious species must be eradicated by landowners. They are non-native with currently restricted or local distribution in Alberta that present risks of spreading and causing significant economic or ecological impact. They are also non-native species not currently established in Alberta but that occur in neighboring jurisdictions, cause significant economic or ecological impact in those jurisdictions, and are well adapted to Alberta conditions.
The following Prohibited Noxious species are managed under the Weed Control Act
- Autumn Olive — Elaeagnus umbellata Thunb.
- Balsam, Himalayan — Impatiens glandulifera Royle
- Barberry, Common — Berberis vulgaris L.
- Bartsia, Red — Odontites vernus (Bellardi) Dumort
- Buckthorn, Common — Rhamnus cathartica L.
- Cinquefoil, Sulphur — Potentilla recta L.
- Crupina, Common — Crupina vulgaris Pers. ex Cass.
- Dyer’s Woad — Isatis tinctoria L.
- Eurasian Water Milfoil — Myriophyllum spicatum L.
- Flowering Rush — Butomus umbellatus L.
- Garlic Mustard — Alliaria petiolata (M. Bieb.) Cavara & Grande
- Goatgrass, Jointed — Aegilops cylindrica Host
- Hawkweed, Meadow — Pilosella caespitosa Dumort.
- Hawkweed, Mouse-ear — Pilosella officinarum L.
- Hawkweed, Orange — Pilosella aurantiaca L.
- Hoary Alyssum — Berteroa incana (L.) DC.
- Hogweed, Giant — Heracleum mantegazzianum Sommier & Levier
- Iris, pale yellow — Iris pseudacorus L.I
- Knapweed, Bighead — Centaurea macrocephala Puschk. ex Willd.
- Knapweed, Black — Centaurea nigra L.
- Knapweed, Brown — Centaurea jacea L.
- Knapweed, Diffuse — Centaurea diffusa Lam.
- Knapweed, Hybrid — Centaurea × psammogena Gáyer
- Knapweed, Meadow — Centaurea × moncktonii C. E. Britton
- Knapweed, Russian — Rhaponticum repens (L.) Hidalgo
- Knapweed, Spotted — Centaurea stoebe L. ssp.micranthos (Gugler) Hayek
- Knapweed, Squarrose — Centaurea virgata Lam. ssp.squarrosa (Willd.) Gugler
- Knapweed, Tyrol — Centaurea nigrescens Willd.
- Knotweed, Giant — Fallopia sachalinensis (F. Schmidt Petrop.)Ronse Decr.
- Knotweed, Hybrid Japanese — Fallopia × bohemica (Chrtek & Chrtková) J. P. Bailey
- Knotweed, Japanese — Fallopia japonica (Houtt.) Ronse Decr.
- Loosestrife, Purple — Lythrum salicaria L.
- Medusahead — Taeniatherum caput-medusae (L.) Nevski
- Nutsedge, Yellow — Cyperus esculentus L.
- Puncturevine — Tribulus terrestris L.
- Ragwort, Tansy — Jacobaea vulgaris Gaertn.
- Rush Skeletonweed — Chondrilla juncea L.
- Saltcedar — Tamarix ramosissima Ledeb.
- Saltlover — Halogeton glomeratus (M. Bieb.) C.A. Mey.
- St John’s-wort, Common — Hypericum perforatum L.
- Starthistle, Yellow — Centaurea solstitialis L.
- Tamarisk, Chinese — Tamarix chinensis Lour.
- Tamarisk, Smallflower — Tamarix parviflora DC.
- Thistle, Marsh — Cirsium palustre (L.) Scop.
- Thistle, Nodding — Carduus nutans L.
- Thistle, Plumeless — Carduus acanthoides L.