Bitternut Hickory

Carya cordiformis

Pollinator Value

🔑 Keystone: Genus Carya supports 186 species of butterflies and moths as a caterpillar host plant in the Ottawa ecoregion. Bitternut hickory is one of only two native Carya species in the region and is a critical larval host for spectacular saturniids including luna moth (Actias luna), polyphemus moth (Antheraea polyphemus), io moth (Automeris io), and cecropia silkmoth (Hyalophora cecropia). The hickory tussock moth (Lophocampa caryae) is closely associated with this genus.
S13 186 lepidoptera; S14 30 host records
🐛 Larval Host: Amorpha juglandis, Lochmaeus manteo, Xanthotype sospeta, Papilio glaucus, Acronicta funeralis, Campaea perlata, Actias luna, Euclea delphinii, Lophocampa caryae, Schizura concinna, Antheraea polyphemus, Automeris io, Hyalophora cecropia, Orgyia leucostigma
S13+S15 14 verified Eastern NA
❄️ Winter Food Source: Carya nuts provide winter food for Rose-breasted Grosbeak and historically for Ivory-billed Woodpecker. However, bitternut hickory nuts are exceptionally bitter and largely avoided by squirrels and other mammals. The nuts persist on the tree into early winter (Sep-Dec) before husks split and nuts drop, offering limited but real foraging for woodpeckers and other bark-gleaning birds.
S57 2 bird species at genus level; S10 nuts very bitter, little wildlife use; S41 fruits disperse Sep-Dec

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: Secure in Ontario (S5) but Vulnerable in Quebec (S3), reflecting the species' position near the northeastern limit of its range. Not listed under SARA or COSEWIC. Quebec populations are sparse compared to Ontario, concentrated in the St. Lawrence Lowlands and Ottawa Valley.
S22 ON=S5, QC=S3; S26 not SARA listed; S63 sparse in Quebec
Rarity Ranks: QC S3 – Vulnerable, ON S5 – Secure
Migration: Stable
Ecological Context: Bitternut hickory occupies moist bottomlands, streambanks, and rich mesic hardwood forests in the Ottawa Valley. In southern Quebec, it forms a recognized sugar maple-bitternut hickory subtype on deep soils, associated with basswood, eastern hophornbeam, northern red oak, butternut, and black maple. It tolerates a wide range of soils from rich floodplain loams to dry gravelly uplands, but reaches greatest size on rich bottomlands.
S41 sugar maple-bitternut hickory subtype in s. QC; S10 bottomland woodlands, protected river valleys; S7 beech-maple and mixed hardwood stands

Roles: Fire Retardant, Fortress/Barrier, Wildlife Habitat
S73/S29/S72 Evidence: Fire Retardant: S73 [MEDIUM]: S11 Fire Tolerance = Medium (not definitional)] | Fortress/Barrier: S61 keyword match: thorns? (supporting signal only)] | Wildlife Habitat: S72 Hemenway (tables: 10-1, pp. 149)]
Notes: Functions as a canopy-layer wildlife habitat tree in permaculture guilds. In natural forest settings, it associates with sugar maple, basswood, and northern red oak on rich mesic sites. Its deep taproot accesses nutrients from lower soil horizons, and its late leafing (late May-June) allows spring ephemeral understory plants extended light. The dense root system makes it more transplantable than other hickories, offering potential as rootstock for pecan grafting.
S41 associates; S72 tall_tree wildlife_habitat; S29 Woodland Garden Canopy; S41 rootstock for grafting

Category: Dermatological Aid, Diuretic, Laxative, Panacea
S28 Iroquois Dermatological Aid, Meskwaki Diuretic+Laxative+Panacea
Notes: The Iroquois used nut meat oil for the hair, either alone or mixed with bear grease. The Meskwaki prepared an infusion of bark taken as a diuretic, laxative, and general remedy for simple sicknesses. The oil from the seeds was also used in the treatment of rheumatism.
S28 Iroquois Drug + Meskwaki Drug uses; S29 antirheumatic, diuretic, laxative

✅ Edible

Foraging Notes: Nuts are thin-shelled but extremely bitter and astringent. The Iroquois extracted oil from crushed nut meats by boiling, using it as a delicacy in corn bread and pudding, as gravy seasoned with salt, and mixed with corn soup and hominy. Nut meat oil was also added to the mush used by the False Face Societies. The oil was mixed with bear grease for hair treatment and mosquito repellent. Despite historical Indigenous use, the nuts are not commonly eaten today due to their intense bitterness.
S28 12 Iroquois food uses; S29 bitter and astringent; S10 meat of the nut is very bitter