Buffalobur

Discuss this plant with the guide — choose this profile as a possible match and prepare your observations for Colorado Plants & Practical Care.

Solanum rostratum

Great Plains native; documented in Colorado. I-buffalobur U-buffalobur

Sharp spines; toxic to livestock. Native status, garden use and noxious-weed class are separate from toxicity. Exposure help.

Identification caveat: Washington lists this plant as a noxious weed in that state. That legal designation is not transferred to Colorado.

Still researching this plant

This is a sourced working profile. Evidence is incomplete for People, Dogs & cats. Identification and source-photo limits are explained below. Independent botanical and veterinary review is pending. Uncertainty is not a finding that the plant is safe.

Three views of this plant

Photos are source-identified examples, not a complete identification key. Check leaves, stems, flowers and fruit together. Locations are not assumed to be in Colorado.

Solanum rostratum: Deeply lobed leaves and prickly stems, with a yellow flower visible at the edge. — **leaves and prickles** — Deeply lobed leaves and prickly stems, with a yellow flower visible at the edge.
Juan Carlos Fonseca Mata · CC BY-SA 4.0
Photo source and identification
Original record · Original image
Wikimedia Commons source file title and species metadata identify the taxon. Visible morphology was checked for consistency, not treated as an independent botanical determination.
No edits to the downloaded image. Wikimedia may have supplied a scaled thumbnail; original and download URLs are recorded separately. Gallery display preserves the full image; the catalog preview uses a CSS crop.

Solanum rostratum: Side view of a yellow buffalo-bur flower showing unequal stamens, hairy buds, and conspicuous prickles. — **flower detail** — Side view of a yellow buffalo-bur flower showing unequal stamens, hairy buds, and conspicuous prickles.
Dcrjsr · CC BY 4.0
Photo source and identification
Original record · Original image
Wikimedia Commons source file title and species metadata identify the taxon. Visible morphology was checked for consistency, not treated as an independent botanical determination.
No edits to the downloaded image. Wikimedia may have supplied a scaled thumbnail; original and download URLs are recorded separately. Gallery display preserves the full image; the catalog preview uses a CSS crop.

Solanum rostratum: A spreading buffalo-bur plant in rocky soil, with lobed leaves, yellow flowers, and spiny fruiting structures. — **whole plant** — A spreading buffalo-bur plant in rocky soil, with lobed leaves, yellow flowers, and spiny fruiting structures.
Dcrjsr · CC BY 4.0
Photo source and identification
Original record · Original image
Wikimedia Commons source file title and species metadata identify the taxon. Visible morphology was checked for consistency, not treated as an independent botanical determination.
No edits to the downloaded image. Wikimedia may have supplied a scaled thumbnail; original and download URLs are recorded separately. Gallery display preserves the full image; the catalog preview uses a CSS crop.

Recognize

Yellow, five-lobed flowers; deeply lobed leaves with conspicuous spines on the veins and stems. This is an annual. I-buffalobur

Plants & habitat

Can compete strongly with forage in disturbed pastures. Prevent seed production where removal is needed. W-buffalobur

People

The abundant spines present a puncture hazard. Use sturdy gloves for removal; this is a physical-risk inference from the documented spines. Human ingestion effects are not established here. I-buffalobur

Evidence scope: Documented spines; editorial risk inference.

Dogs & cats

Spines may injure paws or mouths. Pet-specific chemical toxicity is not established by the livestock source; prevent chewing. W-buffalobur

Evidence scope: Physical-risk inference; pet evidence gap.

Other animals

Reported toxic to livestock; burs also catch in sheep wool. W-buffalobur

Before taking action

Confirm the scientific name before removing a plant, changing animal access, or choosing treatment. An evidence gap means this review has not resolved the question. It does not mean safe. For listed weeds, consult your county weed program about the requirements for your location; follow the current label for any pesticide. S27

References

I-buffalobur — Buffalobur, Iowa State University Extension. Accessed 2026-09-07T00:27:17+00:00. Locator: Description, distribution, hazards, management; see claim locator.
U-buffalobur — Solanum rostratum herbarium collection records, University of Colorado Museum of Natural History. Accessed 2026-09-07. Locator: COLO:V specimens 00785139 and 00785204; Colorado localities.
W-buffalobur — Buffalobur, Washington State Noxious Weed Control Board. Accessed 2026-09-07T00:27:17+00:00. Locator: Description, distribution, hazards, management; see claim locator.

Content revised 2026-09-07 02:43:00Z · Source checks dated separately in the references.