Canada Tick-trefoil

Desmodium canadense

Pollinator Value

🐛 Larval Host: Strymon melinus (Gray Hairstreak), Thorybes pylades (Northern Cloudywing), Achalarus lyciades (Hoary Edge)
S14 NHM HOSTS 3 records; all present in ON/QC
❄️ Winter Food Source: Jointed loments persist on erect stems into winter, providing seed for Ruffed Grouse and Northern Bobwhite. Seeds are also consumed by Wild Turkey, White-Footed Mouse, and other small rodents.
S57 Ruffed Grouse 28.6% occurrence, Northern Bobwhite 12.1%; S29 seeds used by upland gamebirds and small rodents

Proximity Score: 0
Native Status: ✅ Outaouais ✅ Ottawa ✅ QC ✅ ON
Closest Direction: Local
CEC Eco-Regions: 5 – Northern Forests, 5.2 – Mixed Wood Shield, 5.2.3 – Algonquin/Southern Laurentians
Rarity Notes: Globally secure (G5) and nationally secure (N5) in both Canada and the United States. Ranked S4 in both Ontario and Quebec. Not listed under SARA or COSEWIC. Uncommon in the Ottawa region per Brunton 2005, sparse on the Quebec side per Gillett and White 1978.
S22 G5, N5, S4 ON/QC; S26 not SARA listed; S62 Uncommon in Ottawa; S63 Sparse in Quebec
Rarity Ranks: QC S4 – Apparently Secure, ON S4 – Apparently Secure
Migration: Stable
Ecological Context: Inhabits open woods, rocky or sandy prairies, stream banks, and forest edges. In the Ottawa-Gatineau region, found along the Ottawa River floodplain and tributaries such as the Rideau River. Associates with tallgrass prairie remnants and open sandy or gravelly habitats. Tolerates a range of moisture conditions from dry sandy knolls to wet meadows.
S4 open woods, prairies, stream banks; S7 river banks, wet prairies, fens, borders of forests; S48 specimens from Rideau River, Shirley's Bay, Petrie Islands; S61 floodplain, forest edges, meadows

Roles: Fortress/Barrier, Insectary Plant, Pollinator Attractor
S73/S29/S72 Evidence: Fortress/Barrier: S61 keyword match: thorns? (supporting signal only)] | Insectary Plant: S64 NPPBI 'beneficial insects' flag] | Pollinator Attractor: S73 [HIGH]: S64 Xerces listed (source-classified)]
Notes: As a legume, Desmodium canadense fixes atmospheric nitrogen via rhizobial symbiosis, enriching soil for neighbouring plants. Its deep taproot acts as a dynamic accumulator, drawing nutrients from lower soil horizons. Dense flower clusters attract beneficial insects including bumble bees and parasitoid wasps, functioning as an insectory plant in polyculture designs.
S29 nitrogen fixer, dynamic accumulator, insectory; S64 bumble bee plant, beneficial insects; S71 evidence framework

Category: Gastrointestinal Aid
S28 Iroquois Drug, Gastrointestinal Aid
Notes: The Iroquois used a decoction of the root as a gastrointestinal aid, taken for biliousness (Herrick 1977). PFAF rates medicinal value at 0/5, indicating no widely recognized modern medicinal applications.
S28 Moerman: Iroquois Drug, Gastrointestinal Aid, root decoction for biliousness; S29 Medicinal Rating 0/5

❌ Not Edible

Foraging Notes: No documented edible uses. PFAF rates edibility at 0/5 and Moerman lists no food uses for this species.
S29 Edibility Rating 0/5; S28 no Food category uses