Southern and Central Ontario (Zones 4–6) are home to some of the rarest plant habitats in the province, like tallgrass prairies, oak savannahs, alvars, fens, dunes, and Carolinian forests. The plants that live there aren’t “just uncommon”… many are officially at risk.

Learning which species are endangered (and why) helps gardeners make better choices at home, protecting native habitat, avoiding invasive plants, and supporting biodiversity in a real, local way. 

At Ritchie’s, we’re working to be part of the solution through education and steady expansion of our native plant offerings, staying in close contact with growers and improving access to native choices that support Ontario ecosystems.

Forest and woodland species

• American Ginseng (Panax quinquefolius)
  Found in rich, mature hardwood forests; vulnerable to poaching and slow to reproduce.
• Goldenseal (Hydrastis canadensis)
  Woodland herb historically used medicinally; threatened by habitat loss and collection pressure.
• Spotted Wintergreen (Chimaphila maculata)
  Found in dry woodlands; sensitive to changes in forest conditions.
• Cucumber Tree (Magnolia acuminata)
  Canada’s only native magnolia, found in the Carolinian zone.
• Red Mulberry (Morus rubra)
  Carolinian forest tree; rare in Ontario and impacted by habitat loss and hybridization pressure.
• Butternut (Juglans cinerea)
  Declining due to butternut canker, a serious fungal disease.

Prairie and savannah species

• Bird’s-foot Violet (Viola pedata)
  Associated with oak savannahs and tallgrass prairies.
• Dense Blazing Star (Liatris spicata)
  Found in moist prairies and abandoned fields (not the same as the common garden liatris you often see in stores).
• Eastern Prairie Fringed-orchid (Platanthera leucophaea)
  A rare orchid found in prairies, fens, and sedge meadows.
• Small White Lady’s-slipper (Cypripedium candidum)
  Rare orchid of fens and prairies; extremely sensitive to disturbance.
• Forked Three-awned Grass (Aristida basiramea)
  Occurs on shallow soils over bedrock; tied to specific open habitat conditions.

Alvars, fens, dunes, and shorelines

• Houghton’s Goldenrod (Solidago houghtonii)
  Found in coastal fens and alvars.
• Pitcher’s Thistle (Cirsium pitcheri)
  A Great Lakes dune species; specialized to sandy shoreline habitats.
• Eastern Prickly Pear Cactus (Opuntia cespitosa)
  Found on sandy beaches and dunes; threatened by habitat disturbance.
• Purple Twayblade (Liparis liliifolia)
  Rare orchid with limited populations in Ontario.

Threatened and other rare species you may see mentioned

Some plants in Zones 4–6 are listed as Threatened (not endangered, but still at risk), or are considered rare and declining.

Examples include:

• Blue Ash (Fraxinus quadrangulata), threatened by emerald ash borer
• Climbing Prairie Rose (Rosa setigera),  open woods and thickets
• Colicroot (Aletris farinosa), allgrass prairie species

What this means for gardeners 
(the helpful, practical part)

You can absolutely make a difference, without needing to live beside a prairie or an alvar.

1) Don’t wild-harvest

A lot of Ontario’s rare plants decline because they’re removed from the wild. Even “one plant” can matter when populations are small, especially for slow-growing woodland herbs like ginseng.

2) Avoid invasive plants (and choose alternatives)

Invasive species are a major pressure on rare habitat plants. Choosing non-invasive options in home landscapes is one of the biggest everyday actions gardeners can take.

3) Plant habitat, not just decoration

Even small yards can support biodiversity by adding:

• native flowering perennials (season-long blooms)
• shrubs and small trees for structure
• leaf litter / messy winter areas for overwintering insects
• water sources (shallow bird baths, pollinator-friendly watering spots)

4) Support the places these plants live

Tallgrass prairie remnants, savannahs, alvars, dunes, and Carolinian forests need protection and restoration. Supporting local conservation groups and respecting sensitive natural areas helps keep these species on the landscape.

A quick reminder about “garden versions”

Some names in the endangered plant list resemble common garden plants (ex: “blazing star”). That doesn’t mean the standard garden version is endangered, it usually means the specific native species or genotype in Ontario is rare.

If you’re unsure, we can always help you choose native-friendly, non-invasive options that give you a similar look while supporting local ecosystems.

Want to garden in a way that supports Ontario’s native habitats?

Start small: choose non-invasive plants, add a few pollinator favourites, and leave a little habitat through winter. Those choices add up fast across a community, and they’re one of the most realistic ways home gardeners can help protect the plants that can’t “move” when their habitat disappears.