Species At Risk

Swamp Rose-mallow

(Hibiscus moscheutos)

Special Concern

Swamp Rose-mallow
Swamp Rose-mallow occurrences map


The Swamp Rose-mallow is a perennial member of the mallow family. Reaching about two metres in height, this large wetland plant produces showy, pink or white-petalled flowers in summer. The petals measure six to 10 centimetres long. Each flower opens for one or two days, and fades as soon as it is pollinated. Leaves are alternate and variable in shape from lance-like to three-lobed.

Action we are taking:


The Swamp Rose-mallow range in North America extends from the lower Great Lakes region south to Florida and west to New Mexico. It may be adventive (introduced and locally common) farther west. In Ontario, it has been found at approximately 60 to 70 sites and is believed to currently occur at about 50 sites. Most sites are in coastal marshes of Lake Erie and Lake St. Clair. However, in the last 15 years, plants have colonized sites on the shores of Lake Ontario, expanding the distribution northwards. The species has also been introduced to Europe where it is locally common.


In Ontario, Swamp Rose-mallow is restricted to shoreline marshes, in the Carolinian and Great Lakes - St. Lawrence forest regions, associated with lakes Erie, Ontario or St. Clair.

Swamp Rose-mallow is most commonly found in deep-water cattail marshes and in meadow marshes. It reaches its greatest numbers in dyked wetlands, where competition from other plants is controlled and the open habitat is maintained by periodic flooding. It is also found in open wet woods, thickets, spoil banks, and drainage ditches.


Wetland drainage, shoreline development, and the spread of invasive species, are the main threats for the Swamp Rose-mallow in Ontario. Through natural succession, its habitat can be gradually overtaken by shrubs unless kept open by periodic flooding or fire. Two invasive plants, European Common Reed (Phragmites australis subsp. australis) and Hybrid Cattail (Typha x glauca), have recently spread into some of the sites, where they crowd out Swamp Rose-mallow and other native plants.


Swamp Rose-mallow is listed as a species of Special Concern under Ontario’s Endangered Species Act. Although species of Special Concern do not receive legal protection under this act, there are large populations of Swamp Rose-mallow in provincial parks and conservation lands where they get some protection. In Ontario, most Swamp Rose-mallow plants are growing on private property.

What You Can Do to Help the Swamp Rose-mallow

  • The Ministry of Natural Resources tracks species at risk such as the Swamp Rose-mallow. You can use a handy online form to report your sightings to the Natural Heritage Information Centre. Photographs with specific locations or mapping coordinates are always helpful. nhic.mnr.gov.on.ca
  • Report any illegal activity related to plants and wildlife to 1-877-TIPS-MNR (847-7667).
  • Private land owners have a very important role to play in species recovery. You may be eligible for stewardship programs that support the protection and recovery of species at risk and their habitats.
  • Volunteer with your local nature club or provincial park to participate in surveys or stewardship work focused on species at risk.
  • Invasive species seriously threaten many of Ontario’s species at risk. To learn what you can do to help reduce the threat of invasive species, visit: ontario.ca/invasivespecies ; www.invadingspecies.com ; www.ontarioinvasiveplants.ca ; and, www.invasivespecies.gc.ca .

Did you know?

The total Canadian population of Swamp Rose-mallow is estimated to consist of fewer than 10,000 plants.

Did you know?

Water level fluctuations that periodically expose and then re-flood – thus controlling phragmites, shrubs, and small trees – are probably critical for the long-term survival of this species in Canada.

The Endangered Species Act

Contact your local ministry office

Often the best source of local information on species at risk is your nearest ministry office. Call with your questions or concerns.