Flower profile

Blackroot

Pterocaulon pycnostachyum

Blackroot (Pterocaulon pycnostachyum) is a low shrub in the Asteraceae family, native in the lower 48 states, blooming mostly April–June across the U.S.

Native to Florida

Blackroot is a wildflower that USDA PLANTS lists as native in the lower 48 states. In Florida it's most often seen in bloom in April–June.

6states where USDA records it

5,795FL sightings*

6,638U.S. sightings*

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

On our lists for: Florida

Quick look

Pterocaulon pycnostachyum, with the common names dense-spike blackroot, fox-tail blackroot or coastal blackroot, is a flowering plant species native to the U.S. southeast coastal plain in the states of Alabama, Mississippi, North Carolina, Florida, Georgia, and South Carolina. It can be found in pinelands, ditches, depressions, and fields.
From Wikipedia's article Pterocaulon pycnostachyum, CC BY-SA 4.0.

It belongs to the Asteraceae family. ^iNaturalist
USDA PLANTS describes it as an herb (forb) / a subshrub with a perennial life cycle. ^{USDA PLANTS}
USDA PLANTS lists it as native in the lower 48 states and records it in 6 states. ^{USDA PLANTS}
NatureServe lists it as native to Florida. ^NatureServe
In Florida, most iNaturalist sightings of it in flower come in April–June. ^iNaturalist
iNaturalist has 5,795 research-grade sightings of it in Florida, ranking #28 among the 151 flowers on our Florida list. ^iNaturalist

When does it bloom?

In Florida, most flowering sightings come in April–June.

Flowering records by month in Florida (iNaturalist research-grade observations marked “Flowering”) (141 records)

Conservation status

Federal (U.S. ESA): Not listed No U.S. Endangered Species Act listing in the USFWS ECOS database. ^{USFWS ECOS}
NatureServe global: G5 Secure worldwide. ^NatureServe
Florida: Not listed Not on Florida Regulated Plant Index (Fla. Admin. Code 5B-40.0055). NatureServe: S5, secure in Florida. ^{FAC 5B-40.0055}
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 blackroot in 6 states.

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recorded by USDA PLANTS on our state lists not recorded

See the full list of states

Alabama, Florida, Georgia, Mississippi, North Carolina, South Carolina.

Florida counties with USDA records: Alachua, Baker, Bay, Bradford, Brevard, Broward, Calhoun, Charlotte, Citrus, Clay, Collier, Columbia, DeSoto, Duval, Escambia, Flagler, Franklin, Gilchrist, Glades, Gulf, Hamilton, Hardee, Hendry, Hernando, Highlands, Hillsborough, Indian River, Jefferson, Lafayette, Lake, Lee, Leon, Levy, Liberty, Manatee, Marion, Martin, Miami-Dade, Monroe, Nassau, Okaloosa, Okeechobee, Orange, Osceola, Palm Beach, Pasco, Pinellas, Polk, Putnam, Santa Rosa, Sarasota, Seminole, St. Lucie, Sumter, Suwannee, Taylor, Union, Volusia, Wakulla, Walton, Washington.

Names, range and relatives

Other scientific names (synonyms in USDA PLANTS): Pterocaulon undulatum.

County records: USDA PLANTS lists it in 120 counties across 5 states; the most are in Florida (61), Georgia (24), South Carolina (22).

More from the Asteraceae family (212 on Bloomipedia; most observed first): Common yarrow, Goldenrods, White snakeroot, Sunflowers, Chicory, Black-eyed Susan, Bull thistle, Common dandelion.

More Florida flowers

White beggarticks

Bidens alba

Native

🌼 Blooms in FL: January–March

Trailing daisy

Sphagneticola trilobata

Introduced

🌼 Blooms in FL: June–November

Bristle thistle

Cirsium horridulum

Native

🌼 Blooms in FL: March–April

Sources

USDA, NRCS. PLANTS Database, profile PTPY2.
iNaturalist, Pterocaulon pycnostachyum: taxonomy, research-grade observation counts and “Flowering” annotations, retrieved October 17, 2026.
Wikipedia, Pterocaulon pycnostachyum (lead quoted under CC BY-SA 4.0).
Florida: Florida Regulated Plant Index (Fla. Admin. Code 5B-40.0055).
Florida: Florida Noxious Weed List (Fla. Admin. Code 5B-57.007).
USFWS, ECOS species database (ESA listing check), October 17, 2026.
NatureServe Explorer, Pterocaulon pycnostachyum (global and state ranks).
Edibility and toxicity: no source found (marked "not well documented").
Photo: Laura Gaudette via iNaturalist · CC BY 4.0 · resized.