Asclepias incarnata

L.

Swamp Milkweed

G5Secure Found in 28 roadless areas NatureServe Explorer →
G5SecureGlobal Rank
Least concernIUCN
UnknownThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.129944
Element CodePDASC020U0
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
IUCNLeast concern
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderGentianales
FamilyApocynaceae
GenusAsclepias
Other Common Names
Asclépiade incarnate (FR) swamp milkweed (EN)
Concept Reference
Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2024-05-16
Change Date1984-02-09
Edition Date2024-05-16
Edition AuthorsSoteropoulos (2024)
Threat ImpactUnknown
Range Extent>2,500,000 square km (greater than 1,000,000 square miles)
Number of Occurrences> 300
Rank Reasons
Asclepias incarnata is a wide-ranging perennial herb occurring throughout North America, from Nova Scotia west to Manitoba in Canada south to Florida and Arizona in the United States and Coahuila, Mexico. There are two subspecies, with the typic most common west of the Appalachian Mountains and ssp. pulchra most common on the coastal plain east of the Appalachian Mountains. Commonly cultivated, estimating the number of wild populations is challenging. Threats include development, roadside maintenance activities, and invasive species. With a large range extent and number of occurrences, abundant habitat, broad habitat preferences, and no obvious intrinsic vulnerabilities, this species is considered secure.
Range Extent Comments
Asclepias incarnata occurs throughout North America, from Nova Scotia west to Manitoba in Canada south to Florida and Arizona in the United States and Coahuila, Mexico (FNA 2023). There are two subspecies, with the typic "most common west of the Appalachian Mountains and is the only one commonly found in Florida" and ssp. pulchra "most common on the coastal plain east of the Appalachian Mountains" (FNA 2023). Range extent was estimated to be over 8.8 million square kilometers using herbarium specimens, photo-based observations, and NatureServe Network occurrence data documented between 1993 and 2024 (GBIF 2024, iNaturalist 2024, NatureServe 2024, SEINet 2024).
Occurrences Comments
By applying a 1 km separation distance to herbarium specimens, photo-based observations, and NatureServe Network occurrence data documented between 1993 and 2024, it is estimated that there are well over 5,000 occurrences rangewide (GBIF 2024, iNaturalist 2024, NatureServe 2024, SEINet 2024). However, this taxon is commonly cultivated, and iNatualist observations (>28,000, mostly identified at the species-level) were not evaluated for evidence of cultivation (iNaturalist 2024).
Threat Impact Comments
Although threats are not widely documented, this species is potentially threatened by development, rights-of-way maintenance, wild collection, invasive species, and other threats in some places.
Ecology & Habitat

Habitat

Asclepias incarnata grows in "a great variety of soil types and is surprisingly drought tolerant consid­ering its natural predilection for hydric and mesic soils," which includes bogs, marshes, swamps, creeks, ditches, streamsides, pond and lake shores, wet meadows and prairies, riparian woods, mixed hardwood forests, flatwoods, hammocks, and thickets (FNA 2023).
Terrestrial Habitats
Woodland - HardwoodWoodland - ConiferWoodland - MixedShrubland/chaparralGrassland/herbaceousOld field
Palustrine Habitats
TEMPORARY POOLHERBACEOUS WETLANDSCRUB-SHRUB WETLANDFORESTED WETLANDBog/fenRiparian
Other Nations (2)
CanadaN5
ProvinceRankNative
OntarioS5Yes
ManitobaS3Yes
New BrunswickS4Yes
QuebecSNRYes
AlbertaSNANo
Prince Edward IslandS2Yes
SaskatchewanSNANo
Nova ScotiaS4Yes
United StatesN5
ProvinceRankNative
New JerseySNRYes
IndianaS5Yes
NevadaS1Yes
South CarolinaSNRYes
FloridaSNRYes
IllinoisSNRYes
MinnesotaSNRYes
MississippiS1Yes
TennesseeSNRYes
OklahomaSNRYes
IowaS5Yes
VirginiaS5Yes
WyomingS2Yes
District of ColumbiaSNRYes
South DakotaSNRYes
VermontS5Yes
ArizonaS1Yes
MassachusettsSNRYes
MaineSNRYes
New YorkS5Yes
North CarolinaS5Yes
WisconsinSNRYes
PennsylvaniaS5Yes
MichiganSNRYes
AlabamaSNRYes
UtahS2Yes
North DakotaSNRYes
TexasSNRYes
ConnecticutSNRYes
GeorgiaS3Yes
DelawareS5Yes
MarylandSNRYes
Rhode IslandSNRYes
MontanaS1Yes
New HampshireSNRYes
West VirginiaS5Yes
New MexicoSNRYes
OhioSNRYes
LouisianaS2Yes
NebraskaSNRYes
IdahoS2Yes
KansasSNRYes
MissouriSNRYes
KentuckySNRYes
ColoradoS4Yes
ArkansasS2Yes
Threat Assessments
ThreatScopeSeverityTiming
Unknown/undetermined

Plant Characteristics
DurationPERENNIAL
Economic Value (Genus)Yes
Roadless Areas (28)
Idaho (1)
AreaForestAcres
Bear CreekCaribou-Targhee National Forest118,582
Montana (1)
AreaForestAcres
West Big HoleBeaverhead-Deerlodge National Forest133,563
Nevada (1)
AreaForestAcres
Rose - EvansHumboldt-Toiyabe National Forest4,782
North Carolina (2)
AreaForestAcres
Chunky Gal (addition)Nantahala National Forest3,336
Woods MountainPisgah National Forest9,602
North Dakota (4)
AreaForestAcres
DurlerDakota Prairie Grasslands12,464
McleodDakota Prairie Grasslands9,117
SheyenneDakota Prairie Grasslands14,537
VenloDakota Prairie Grasslands5,317
Pennsylvania (3)
AreaForestAcres
Allegheny FrontAllegheny National Forest7,430
CornplanterAllegheny National Forest2,929
Tracy RidgeAllegheny National Forest9,034
Tennessee (2)
AreaForestAcres
Beaver Dam CreekCherokee National Forest5,070
Flint Mill GapCherokee National Forest9,494
Utah (2)
AreaForestAcres
Lewis PeakWasatch-Cache National Forest11,616
WellsvilleWasatch-Cache National Forest1,717
Vermont (1)
AreaForestAcres
Griffith Lake 09084Green Mountain and Finger Lakes National Forests1,833
Virginia (6)
AreaForestAcres
Bear CreekJefferson National Forest18,274
Elliott KnobGeorge Washington National Forest9,380
Little Wilson Creek Addition BJefferson National Forest1,725
Northern MassanuttenGeorge Washington National Forest9,444
Peters Mountain Addition BJefferson National Forest2,909
Seng MountainJefferson National Forest6,428
West Virginia (3)
AreaForestAcres
Canaan LoopMonongahela National Forest7,867
Cranberry AdditionMonongahela National Forest11,123
Dolly Sods Roaring PlainMonongahela National Forest13,392
Wisconsin (2)
AreaForestAcres
09011 - Flynn Lake Study AreaChequamegon-Nicolet National Forest5,951
09154 - St. Peters DomeChequamegon-Nicolet National Forest4,002
References (8)
  1. Flora of North America Editorial Committee (FNA). 2023. Flora of North America north of Mexico. Vol. 14. Magnoliophyta: Gentianaceae to Hydroleaceae. Oxford Univ. Press, New York. xxiv + 505 pp.
  2. Global Biodiversity Information Facility (GBIF). 2024. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2024).
  3. Heidel, B. 1994b. Sensitive species survey of Bluewater Fish Hatchery of 10 June; memo and documentation provided to Gary Shaver, MDFWP.
  4. Heidel, B. 1994c. Potential impact of proposed noxious weed treatment at Bluewater Fish Hatchery (MDFWP) on plant species of special concern. Unpublished report to Gary Shaver, Bluewater Fish Hatchery. Montana Natural Heritage Program, Helena, Montana. 5 pp.
  5. iNaturalist. 2024. Online. Available: https://www.inaturalist.org (accessed 2024).
  6. Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
  7. NatureServe. 2024. NatureServe Network Biodiversity Location Data. NatureServe, Arlington, Virginia.
  8. Southwest Environmental Information Network (SEINet). 2024. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2024).