Species At Risk

Round-leaved Greenbrier

(Smilax rotundifolia)


Round-leaved Greenbrier
Round-leaved Greenbrier occurrences map


Round-leaved Greenbrier is a woody, climbing vine that can grow to over six metres in length as it wraps around shrubs and trees. The main stems are rounded and have flattened prickles. The leaves are egg-shaped and about five to 10 centimetres long. The plant produces clusters of small, green flowers that bloom from late May to mid-June. The fruit, which ripens in the fall, is bluish-black in colour and usually contains two seeds.


The species is found across much of eastern North America from southwestern Nova Scotia to northern Florida, eastern Texas and north to eastern Michigan and southwestern Ontario. As of 2007, thirteen populations were known in Ontario.


In Ontario, Round-leaved Greenbrier is found mainly in the warmer climate of the Carolinian Forest. It prefers open moist to wet woodlands, often growing on sandy soil.


The greatest threat to the Round-leaved Greenbrier is habitat degradation and destruction. Ontario populations of Round-leaved Greenbrier persist in habitat fragments and only a few of these populations can reproduce sexually since many appear to consist of all male or all female plants.


Round-leaved Greenbrier is protected under Ontario’s Endangered Species Act and the federal Species at Risk Act.

What You Can Do to Help Round-leaved Greenbrier

  • The Ministry of Natural Resources tracks species at risk such as Round-leaved Greenbrier. 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. If you find Round-leaved Greenbrier on your property, you may be eligible for stewardship programs that support the protection and recovery of species at risk and their habitats.
  • Consult the Ministry of Natural Resources for information on provincial regulations and best management practices when working around wetlands and in forests. Call toll free 1-800-667-1940 or visit the Ministry website at www.mnr.gov.on.ca/en/ContactUs/2ColumnSubPage/STEL02_179002.html.
  • Volunteer with your local nature club or provincial park to participate in surveys or stewardship work focused on species at risk.
  • Pollinators, such as bees, are in steep decline across the globe and they play a key role in the survival of many of Ontario’s rare plants. For information on how you can help scientists monitor pollinator populations in Ontario visit: www.seeds.ca/proj/poll.
  • 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 .
  • The Carolinian forests of southern Ontario support an amazing diversity of plants and wildlife, including many species at risk. Carolinian Canada is working to help recover species at risk and their habitats. For more information, visit: www.carolinian.org/SpeciesHabitats.htm.

Did you know?

The seeds of Round-leaved Greenbrier can remain buried in the soil for at least three years while waiting for the right conditions to start growing a new plant.

Did you know?

The young seedlings of Round-leaved Greenbrier are a popular food for white-tailed deer, which can be a problem for this rare plant in areas with large deer populations.

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.