Prohibited Aquatic Plants

There are several classifications of Invasive Species, as outlined in the Alberta Invasive Species Council’s website at

  • Prohibited Noxious – As per the Weed Control Act, shall be destroyed
  • Noxious – As per the Weed Control Act, shall be controlled
  • Prohibited – As per the Fisheries (Alberta) act, prohibited from import and possession
  • Pest – As per the Agricultural Pests Act, pest species for prevention
  • Nuisance – As per the Agricultural Pests Act, nuisance species for management
  • N/A – species of concern, not yet regulated
Curly leaf Pond weed

Curly Leaf Pondweed – Prohibited

Curly leaf pondweed is a submerged aquatic plant whose life cycle acts like a winter annual. It is native to Eurasia, Africa, and Australia. The first verified report of curly leaf pondweed in North America was in the mid 1800s and in Canada by the end of that century. Today it is spread throughout temperate North America. It forms dense beds which outcompete native aquatic plants, and can interfere with recreational activities as well. It can also increase phosphorus concentrations in the water which increase the incidence of algal blooms. For more detailed information, go to

Frog Bit
Frog Bit

European Frogbit ‘Hydrocharis morsus-ranae’ – Prohibited

European frogbit is an annual aquatic free-floating plant native to Europe and parts of Asia and Africa.

As of January 1, 2016, the possession, sale, or transport of this species in Alberta is illegal under the Fisheries Act. For detailed information, please go to

Flowering Rush ‘Butomus umbellatus’ – Prohibited Noxious

Flowering rush is a cattail-like perennial of freshwater wetlands. It is native to Africa, Asia and Europe and was likely introduced to North America as an ornamental plant. Flowering rush can grow on water margins or as a submerged plant with flexible leaves suspended in deeper water. It can grow in zone 2. For detailed information, go to

Floating Heart ‘Nymphoides peltata’ – Prohibited

Yellow floating heart is a bottom-rooted, aquatic perennial plant with floating leaves. Dense mats of N. peltata block sunlight from reaching native plants and algae, and can impede flow in very slow-moving waters, causing stagnant waters, which reduce
oxygen concentrations. For detailed information, go to

Yellow Iris ‘Iris Pseudocorus’ – Prohibited Noxious

These fast spreading rhizomes can outcompete other plants for space, forming thickets like native cattails. This rhizome
mat creates improved habitat for further infestation by Iris pseudacoris by compacting soils and elevating topography, creating a habitat that is drier with increased siltation and sedimentation. Yellow flag iris is generally unpalatable and
is also poisonous to grazing animals. Cattle experience gastroenteritis and acute diarrhea after eating hay containing yellow flag iris. For detailed information, please go to