Bloomipedia
Santa Maria feverfew (Parthenium hysterophorus)
Photo: Loren Cassin Sackett via iNaturalist · CC BY 4.0 · resized

Flower profile

Santa Maria feverfew

Parthenium hysterophorus

Introduced in the lower 48

Santa Maria feverfew is a wildflower that USDA PLANTS lists as introduced in the lower 48 states. It's on our flower lists for 2 states, and across the U.S. it's most often seen in bloom in March–December.

23states
2of our state lists
10,085U.S. sightings*

*iNaturalist research-grade observations, as of October 17, 2026.

On our lists for: Louisiana, Texas

Quick look

Parthenium hysterophorus is a herbaceous, flowering weed species in the family Asteraceae. It is one of the most common weeds across the globe. It is best known as Santa Maria feverfew, but is also referred to as Santa-Maria, whitetop weed, famine weed and congress grass. It is native to the American tropics but has since become an invasive species in East Asia, India, Australia, and parts of Africa.

  • It belongs to the Asteraceae family. iNaturalist
  • USDA PLANTS describes it as an herb (forb) with a annual life cycle. USDA PLANTS
  • USDA PLANTS lists it as introduced in the lower 48 states and records it in 23 states. USDA PLANTS
  • NatureServe lists it as not native to Texas and Louisiana. NatureServe
  • In Texas, most iNaturalist sightings of it in flower come in March–December. iNaturalist
  • In Louisiana, most iNaturalist sightings of it in flower come in May–December. iNaturalist
  • iNaturalist has 8,321 research-grade sightings of it in Texas, ranking #70 among the 109 flowers on our Texas list. iNaturalist
  • iNaturalist has 537 research-grade sightings of it in Louisiana, ranking #64 among the 109 flowers on our Louisiana list. iNaturalist

Santa Maria feverfew gift ideas

Handmade santa maria feverfew gifts from independent makers.

When does it bloom?

Flowering records by month across the U.S. (iNaturalist research-grade observations marked “Flowering”) (1,088 records)
Bloom time in each of our 2 states
StateTypePeak bloomSightings*
TexasIntroducedMarch–December8,321
LouisianaIntroducedMay–December537

Conservation status

Federal (U.S. ESA)
Not listed No U.S. Endangered Species Act listing in the USFWS ECOS database. USFWS ECOS
NatureServe global
GNR Not yet ranked worldwide. NatureServe
Texas
Not listed Not on Texas endangered and threatened plants (31 Tex. Admin. Code § 69.8), as listed by Texas Parks and Wildlife. NatureServe: SNA, not applicable (usually because it isn't native there) in Texas. 31 TAC 69.8
Louisiana
No list Louisiana has no state list of endangered or threatened plants separate from the federal list, so we show federal status and NatureServe's Louisiana ranks. NatureServe: SNA, not applicable (usually because it isn't native there) in Louisiana.
Rare elsewhere
No other U.S. state ranks it S1, S2, SH or SX.

Checked October 17, 2026. Rankings and lists can change, so follow the links for the latest.

Can you eat it?

For peopleNot well documented

None of the sources we checked (NC State Extension (no page for this plant), USDA PLANTS) say whether it's edible or poisonous for people.

For petsNot well documented

It isn't on the ASPCA plant list.

🌿 Never eat a wild plant unless you're certain of its ID; this isn't medical advice. Worried about a person? Call Poison Control at 1-800-222-1222. Worried about a pet? Call your vet.

Where does it grow?

USDA PLANTS records santa Maria feverfew in 23 states plus Washington, D.C.

recorded by USDA PLANTS on our state lists not recorded

See the full list of states

Alabama, Arkansas, Connecticut, Delaware, Florida, Georgia, Hawaii, Illinois, Kansas, Louisiana, Maryland, Massachusetts, Michigan, Mississippi, Missouri, New Jersey, New York, Ohio, Oklahoma, Pennsylvania, South Carolina, Texas, Virginia; District of Columbia.

Texas counties with USDA records: Anderson, Aransas, Bee, Bell, Bexar, Blanco, Bosque, Brazoria, Brazos, Brewster, Brooks, Brown, Burleson, Burnet, Caldwell, Cameron, Chambers, Childress, Colorado, Comal, Dallas, DeWitt, Fayette, Fort Bend, Galveston, Gillespie, Goliad, Gonzales, Grayson, Guadalupe, Hamilton, Harris, Hays, Hidalgo, Hunt, Jackson, Jefferson, Jim Hogg, Jim Wells, Karnes, Kenedy, Kerr, Kleberg, La Salle, Lampasas, Lavaca, Live Oak, Llano, Maverick, McLennan, Medina, Navarro, Orange, Parker, Refugio, Robertson, San Patricio, San Saba, Tarrant, Taylor, Terrell, Tom Green, Travis, Uvalde, Val Verde, Victoria, Walker, Waller, Wharton, Willacy, Williamson, Young, Zapata.

Louisiana counties with USDA records: Acadia, Assumption, Avoyelles, Beauregard, Caddo, Calcasieu, Caldwell, Cameron, Concordia, East Baton Rouge, East Carroll, Evangeline, Franklin, Grant, Iberia, Iberville, Jefferson, Jefferson Davis, Lafayette, Lafourche, Livingston, Madison, Natchitoches, Orleans, Ouachita, Plaquemines, Pointe Coupee, Rapides, Sabine, St. Bernard, St. Charles, St. James, St. John the Baptist, St. Landry, St. Martin, St. Mary, Tensas, Terrebonne, Vermilion, West Baton Rouge, West Feliciana.

More Texas flowers

Sources