Flower profile

Tall western groundsel

Senecio integerrimus

Tall western groundsel (Senecio integerrimus) is a flowering plant in the Asteraceae family, native in the lower 48 states, blooming mostly April–June across the U.S.

Native to Colorado

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

16states where USDA records it

1,895CO sightings*

5,222U.S. sightings*

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

On our lists for: Colorado

Quick look

Senecio integerrimus is a species of flowering plant in the aster family known by the common names lambstongue ragwort and tall western groundsel. It is native to western and central North America, where it grows in grassland, forest, and other habitat. It is a biennial or perennial herb producing one or a few erect stems 20 to 70 centimeters tall from a caudex with fleshy shallow roots.
From Wikipedia's article Senecio integerrimus, CC BY-SA 4.0.

It belongs to the Asteraceae family. ^iNaturalist
USDA PLANTS describes it as an herb (forb) with a biennial, perennial life cycle. ^{USDA PLANTS}
USDA PLANTS lists it as native in the lower 48 states and records it in 16 states. ^{USDA PLANTS}
NatureServe lists it as native to Colorado. ^NatureServe
In Colorado, most iNaturalist sightings of it in flower come in April–June. ^iNaturalist
USDA PLANTS lists its flower color as yellow. ^{USDA PLANTS}
USDA PLANTS gives its bloom period as mid spring. ^{USDA PLANTS}
USDA PLANTS lists a mature height of about 1.1 ft. ^{USDA PLANTS}
iNaturalist has 1,895 research-grade sightings of it in Colorado, ranking #86 among the 160 flowers on our Colorado list. ^iNaturalist

When does it bloom?

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

Flowering records by month in Colorado (iNaturalist research-grade observations marked “Flowering”) (67 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
Colorado: No list Colorado has no state law listing endangered or threatened plants, so we show NatureServe's Colorado ranks instead. NatureServe: S4, apparently secure in Colorado.
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 peopleToxic (moderate, per USDA)

USDA PLANTS rates its toxicity as “moderate.” (USDA's rating covers people and livestock and doesn't say which parts.) NC State Extension has no page for it. ^{USDA PLANTS}

For petsToxic to dogs, cats and horses

ASPCA's entry “Golden Ragwort” (Senecio species), which covers the whole genus, lists it as toxic to dogs, cats and horses. Signs include: Horses: liver disease (must be ingested in large amount or over a long time… ^ASPCA

🌿 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 tall western groundsel in 16 states.

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recorded by USDA PLANTS on our state lists not recorded

See the full list of states

California, Colorado, Idaho, Iowa, Kansas, Minnesota, Montana, Nebraska, Nevada, New Mexico, North Dakota, Oregon, South Dakota, Utah, Washington, Wyoming.

Colorado counties with USDA records: Boulder, Custer, Douglas, Eagle, El Paso, Elbert, Garfield, Gilpin, Grand, Gunnison, Huerfano, Jackson, Jefferson, Larimer, Las Animas, Lincoln, Mesa, Moffat, Montezuma, Montrose, Park, Rio Blanco, Routt, San Miguel, Summit.

Growing conditions

USDA PLANTS gives Tall western groundsel a medium shade tolerance, low drought tolerance and medium moisture use. It is rated for soil pH 6.5 to 8.5 and winter lows down to -38 °F.

Shade tolerance: Medium
Drought tolerance: Low
Moisture use: Medium
Soil textures it is adapted to: coarse, medium, fine
Soil pH range: 6.5 to 8.5
Minimum temperature tolerated: -38 °F
Frost-free days needed (minimum): 120
Annual precipitation range: 10 to 24 inches
Minimum root depth: 14 inches
Salinity tolerance: Low
Fertility requirement: Medium
Growth rate: Moderate
Lifespan: Moderate
Active growth period: Spring and Summer
Fruit or seed: Brown · Summer to Summer
Can be propagated by: seed
Commercial availability: No Known Source

From the USDA PLANTS characteristics data for SEIN2. USDA ratings are general guidance for the species, not a guarantee for your garden.

Names, range and relatives

Native status by region (USDA PLANTS): Canada: Native; Lower 48 states: Native.

County records: USDA PLANTS lists it in 346 counties across 16 states; the most are in North Dakota (39), Montana (36), Idaho (35).

Other Senecio on Bloomipedia (3): Threadleaf groundsel, Madagascar ragwort, Seabeach groundsel.

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 Colorado flowers

Rubber rabbitbrush

Ericameria nauseosa

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🌼 Blooms in CO: August–October

Common yarrow

Achillea millefolium

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🌼 Blooms in CO: June–September

Dotted gayfeather

Liatris punctata

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🌼 Blooms in CO: July–September

Sources

USDA, NRCS. PLANTS Database, profile SEIN2.
iNaturalist, Senecio integerrimus: taxonomy, research-grade observation counts and “Flowering” annotations, retrieved October 17, 2026.
Wikipedia, Senecio integerrimus (lead quoted under CC BY-SA 4.0).
Colorado: Colorado noxious weed lists A, B and C (8 CCR 1206-2, eff. May 15, 2025).
USFWS, ECOS species database (ESA listing check), October 17, 2026.
NatureServe Explorer, Senecio integerrimus (global and state ranks).
Edibility and toxicity: USDA PLANTS; ASPCA.
Photo: Anders Hastings via iNaturalist · CC BY 4.0 · resized.