PlantKey Open ecological atlas
Planner
Home / Browse / Asclepias / Swamp Milkweed (subsp. incarnata)
iNaturalist — CC, credited & licensed per image
Pictured: Asclepias incarnata — the species. This subspecies isn’t separately illustrated.
Asclepiadaceae family

Swamp Milkweed (subsp. incarnata) Asclepias incarnata subsp. incarnata subspecies

Native ★ Monarch host plant

Swamp Milkweed (subsp. incarnata) is a perennial wildflower native to Canada and the lower 48 states. Monarch host plant.

More about this plant

Asclepias incarnata, the swamp milkweed, rose milkweed, rose milkflower, swamp silkweed, or white Indian hemp, is a herbaceous perennial plant species native to North America. It grows in damp through wet soils and also is cultivated as a garden plant for its flowers, which attract butterflies and other pollinators with nectar. Like most other milkweeds, it has latex containing toxic steroids, a characteristic that repels many species of insects and mammals. Wikipedia →

Growing & care

USDA PLANTS · TRY
Conditions
Sources · Conditions
Cold hardiness (derived) — Hardiness
Hardiness
≥ zone 4 derived from its U.S. range
Size & form
Sources · Size & form
USDA PLANTS — Lifespan
Lifespan
Perennial
In the garden
Herb layer — Sits in the herb of a layered food forest or polyculture.Open guide →
derived roles
Species characteristics from USDA PLANTS (public domain) + TRY (CC BY) — general guidance, not a guarantee for your exact site. Deer "browsing" is documented palatability, not a deer-proof claim.

Wildlife & pollinators

How pollinator value is scored →
★ Monarch Larval host plant

A monarch host plant.

Monarch caterpillars eat only milkweeds (Asclepias). As a native milkweed, Swamp Milkweed (subsp. incarnata) is a documented larval host across its breeding range.

Find milkweed near you Journey North migration map →
Host status from PlantKey's open monarch-host overlay · migration data via Journey North (link)
❧ Caterpillar hosts ~12 caterpillar species

Asclepias supports ~12 caterpillar species.

Native butterfly & moth caterpillars are the base of the terrestrial food web — most songbirds rear their young almost entirely on them. As a host for native Lepidoptera this is a moderate genus.

Recorded feeding on Asclepias in North America, including:

Agathodes designalis · snout moth Cycnia inopinatus · tiger moth Cycnia pudens · tiger moth Cycnia tenera · Delicate Cycnia Danaus eresimus · Soldier Danaus gilippus · Queen
+ 8 more species →
Danaus plexippus · Monarch Ectypia clio · Clio Tiger Moth Euchaetes egle · Milkweed Tussock Moth Euchaetes elegans · Elegant Tussock Moth Hyalophora cecropia · Cecropia Moth Lerina incarnata · Crimson-Bodied Lichen Moth Lycorea cleobaea · brush-footed butterfly Papaipema nebris · Stalk Borer
Keystone count (genus-level) from Warren II 2026 (CC0) · Tallamy host-use records. Named species (a documented Nearctic sample, not exhaustive) from NHM HOSTS (CC0).
Species thumbnails re-hosted from iNaturalist — Creative Commons, credited per image (hover for credit). Click any species to see it on iNaturalist. Not exhaustive; many taxa have no openly-licensed photo yet.
Sources for this entry (13) Open & cited
[01] Scientific name & family — USDA PLANTS (DwCA, Zenodo 17903503)
[02] Growth habit & duration — USDA PLANTS (DwCA, Zenodo 17903503)
[03] Native status & distribution — USDA PLANTS (DwCA, Zenodo 17903503)
[04] Common name — USDA PLANTS (via GBIF)
[05] Invasive / introduced status — USDA PLANTS (DwCA, Zenodo 17903503) — native status
[06] Description — Wikipedia (CC BY-SA)
[07] Ecological value — Warren II 2026 (CC0) · Tallamy host-use counts · Asclepias host rule
[08] Conservation rank — NatureServe Explorer (CC BY)
[09] Cold hardiness (derived) — Derived from U.S. range × USDA PHZM zones
[11] Caterpillar host count — Warren II 2026 (Dryad, CC0) · Tallamy host-use counts
[12] Caterpillar species — NHM HOSTS (CC0)
Spot an error or have a better photo? Every field links to its source, and the whole dataset is open.
Cite this page Open data, please attribute

PlantKey’s data is open under CC BY-SA 4.0 — free to reuse and adapt, with attribution and the same licence. Photos keep their own per-image licence + credit (see Sources above).

Citation

Loading…

BibTeX 
Loading…