Published on August 9, 2023

Discover the Plants and Algae of the Sturgeon River

The Sturgeon River has many native plant species that make up a healthy aquatic ecosystem. Several different types of algae are also common to the river due to its low flow rate.


The Sturgeon River's native plant species include cattails, sedges, various grasses, bulrushes, willows, alder, fireweed and balsam poplar. 

Within the river, there are a few different species of aquatic plants including coontail (or hornwort), northern milfoil, Richardson’s pondweed, sheathed pondweed, sago pondweed and duckweed. Plant growth is heavy in the river because of its high nutrient levels, shallow depth, warm temperature and low flows.

Melissa Logan, Environmental Coordinator, Sturgeon River and Natural Areas for the City of St. Albert, says that several of these names are misnomers. “The pondweeds are not actually weeds, they are submerged aquatic plants and are a natural part of a healthy aquatic ecosystem.”

Bright green duckweed with duck swimming

Photo caption: Duck swimming through bright green duckweed.


Algae growth is common on the Sturgeon River, due to the river’s low flow rate. Algae often gets trapped in the stems of the river’s abundant aquatic vegetation, forming large mats. The photosynthetic organism grows in response to warm water and increased nutrient input.

Blue-green algae may be seen growing in the shallow shoreline areas of the river, which get very warm and provide ideal conditions for its growth. While most algae are harmless, blue-green algae is toxic to humans and dogs if ingested and can cause skin irritation if touched.

Blue Green Algae

Photo caption: This is blue-green algae which is toxic to humans and dogs if ingested and can cause skin irritation if touched.

Melissa says that this type of algae is common in Alberta due to high nutrient levels. “Blue-green algae has been found throughout the sediment record in many Alberta lakes, however it is uncommon to have large blooms in rivers.”

Duckweed is a plant that is often mistaken for algae. However, duckweed is a small, floating aquatic plant that is eaten by ducks. 

“When the duckweed clumps together, it can look like an algae bloom. The plants are actually harmless and serve as an important protein source for ducks. It helps to improve the water quality of the river,” says Melissa.

Duckweed Closeup

Photo caption: Duckweed floating in the Sturgeon River.

Invasive Species

The Sturgeon River has three invasive aquatic plants within the city limits. These are Himalayan balsam, flowering rush and purple loosestrife.  

“Invasive plants often overwhelm native plant species which affects the biodiversity of natural environments,” says Melissa. “This ultimately affects the many organisms that rely on native plants for food or habitat.”

City of St. Albert staff maintain records of where these species are found, how much they spread or are reduced, and are actively trying to control their populations through hand picking. You can learn more and view images of these invasive species on the Weeds of Concern webpage.

The City also organizes outdoor, hands-on, educational workshops that teach students and community members of all ages how to identify and safely remove invasive weeds and support the growth of native plant species. These Weed Warriors events take place each year in the summer. Visit to learn about Weed Warriors events. Keep an eye on the page for 2024 workshop dates.

The City’s Clean and Green RiverFest, happening on Saturday, September 23, is another opportunity for you to help improve the health of the Sturgeon River. This annual event brings volunteers together to collect litter before it enters the river, and plant native trees and shrubs, intended to increase wildlife habitat along the Sturgeon River.

You can learn more about the natural state of the Sturgeon River at


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Last edited: August 9, 2023