---
{
  "id": "common-sunflower",
  "name": "Common sunflower",
  "scientific": "Helianthus annuus",
  "category": "native",
  "status": "Colorado native",
  "status_sources": [
    "S28",
    "S23"
  ],
  "warning": "Listed non-toxic to dogs & cats",
  "warning_tone": "neutral",
  "aliases": [],
  "taxonomy_note": "",
  "source_ids": [
    "S28",
    "S23",
    "S24",
    "S25"
  ],
  "description": "Common sunflower: Listed non-toxic to dogs & cats. Colorado identification, habitat and exposure evidence.",
  "claim_evidence": [
    {
      "label": "Recognize",
      "sources": [
        "S23"
      ],
      "scope": "Species-specific",
      "note": "",
      "reviewed": "2026-09-06",
      "id": "common-sunflower-1"
    },
    {
      "label": "Plants & habitat",
      "sources": [
        "S23"
      ],
      "scope": "Species-specific + garden judgment",
      "note": "Crowding advice is an inference from vigorous self-seeding; no chemical harm to neighboring plants is asserted.",
      "reviewed": "2026-09-06",
      "id": "common-sunflower-2"
    },
    {
      "label": "People",
      "sources": [],
      "scope": "Not assessed",
      "note": "Editorial limit on scope; no claim of human safety.",
      "reviewed": "2026-09-06",
      "id": "common-sunflower-3"
    },
    {
      "label": "Dogs & cats",
      "sources": [
        "S24",
        "S25"
      ],
      "scope": "Species-specific",
      "note": "",
      "reviewed": "2026-09-06",
      "id": "common-sunflower-4"
    },
    {
      "label": "Other animals",
      "sources": [
        "S23",
        "S24"
      ],
      "scope": "Species-specific; livestock not assessed",
      "note": "",
      "reviewed": "2026-09-06",
      "id": "common-sunflower-5"
    }
  ],
  "research": {
    "status": "researching",
    "label": "Still researching this plant",
    "basis": "Editorial assessment of the cited evidence and stated review gaps; not a toxicity score.",
    "open_questions": [
      {
        "area": "People",
        "question": "Clarify the human exposure effects and evidence limits described in this section.",
        "related_claim_ids": [
          "common-sunflower-3"
        ]
      },
      {
        "area": "Other animals",
        "question": "Clarify feeding and exposure risks for each animal group; do not transfer findings between species.",
        "related_claim_ids": [
          "common-sunflower-5"
        ]
      },
      {
        "area": "Expert review",
        "question": "Obtain independent botanical and veterinary review of the identification and hazard summary.",
        "related_claim_ids": []
      }
    ],
    "expert_review": "pending"
  },
  "source": "content/plants/common-sunflower.md"
}
---

# Common sunflower

*Helianthus annuus*

**Colorado native.** [S28](https://pueblo.extension.colostate.edu/loving-our-native-plants/) [S23](https://plants.ces.ncsu.edu/plants/helianthus-annuus/)

> **Listed non-toxic to dogs & cats.** Native status, garden use and noxious-weed class are separate from toxicity. [Exposure help](https://denson.github.io/colorado-weed-field-guide/safety/).

## Still researching this plant {#research-status}

This is a sourced working profile. Evidence is incomplete for **People, Other animals**. 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.

![Helianthus annuus: Front view of a sunflower head, showing yellow ray florets surrounding the darker central disk.](https://denson.github.io/colorado-weed-field-guide/assets/photos/native-helianthus-annuus-1.jpeg)

**flower head** — Front view of a sunflower head, showing yellow ray florets surrounding the darker central disk.

Photo: Michelle W. （鍾偉瑋）; [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/); [source record](https://www.inaturalist.org/observations/61287321); [original image](https://inaturalist-open-data.s3.amazonaws.com/photos/98056702/original.jpeg). The photo belongs to an iNaturalist research-grade observation identified as the named taxon; source taxon, quality grade, and identifications are retained. 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.

![Helianthus annuus: Side and rear view of a sunflower head, showing green involucral bracts and a densely hairy stem.](https://denson.github.io/colorado-weed-field-guide/assets/photos/native-helianthus-annuus-2.jpg)

**back of flower head** — Side and rear view of a sunflower head, showing green involucral bracts and a densely hairy stem.

Photo: lanechaffin; [CC0 1.0](https://creativecommons.org/publicdomain/zero/1.0/); [source record](https://www.inaturalist.org/observations/28073080); [original image](https://inaturalist-open-data.s3.amazonaws.com/photos/43735811/original.jpg). The photo belongs to an iNaturalist research-grade observation identified as the named taxon; source taxon, quality grade, and identifications are retained. 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.

![Helianthus annuus: A yellow sunflower head on a leafy shoot with broad, toothed leaves.](https://denson.github.io/colorado-weed-field-guide/assets/photos/native-helianthus-annuus-3.jpeg)

**flowers and leaves** — A yellow sunflower head on a leafy shoot with broad, toothed leaves.

Photo: Michelle W. （鍾偉瑋）; [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/); [source record](https://www.inaturalist.org/observations/124078954); [original image](https://inaturalist-open-data.s3.amazonaws.com/photos/210274752/original.jpeg). The photo belongs to an iNaturalist research-grade observation identified as the named taxon; source taxon, quality grade, and identifications are retained. 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

An annual with rough, hairy stems and yellow flower rays around darker central disks. [S23](https://plants.ces.ncsu.edu/plants/helianthus-annuus/)

## Plants & habitat

Readily self-seeds and can become weedy. Garden judgment: thin unwanted volunteers where they crowd other plants. [S23](https://plants.ces.ncsu.edu/plants/helianthus-annuus/)

## People

Human ingestion safety is not evaluated in this guide. This profile is not a recommendation to forage.

## Dogs & cats

ASPCA explicitly lists common sunflower as non-toxic to dogs and cats. Any plant material can still upset a pet’s stomach. [S24](https://www.aspca.org/news/plants-support-your-local-wildlife) [S25](https://www.aspca.org/pet-care/aspca-poison-control/toxic-and-non-toxic-plants)

## Other animals

Seeds feed birds and squirrels. Livestock safety is not established by the dog-and-cat source. [S23](https://plants.ces.ncsu.edu/plants/helianthus-annuus/) [S24](https://www.aspca.org/news/plants-support-your-local-wildlife)

## 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](https://planttalk.colostate.edu/topics/weeds-cultural-problems/2103-colorado-noxious-weeds/)

## References

- **S28** — [Loving Our Native Plants](https://pueblo.extension.colostate.edu/loving-our-native-plants/), CSU Extension · Pueblo County. Accessed 2026-09-07T00:23:56+00:00. Locator: Native landscape plant list: Common sunflower and Showy milkweed.
- **S23** — [Helianthus annuus](https://plants.ces.ncsu.edu/plants/helianthus-annuus/), NC State Extension · Plant Toolbox. Accessed 2026-09-07T00:23:56+00:00. Locator: Description; distribution; self-seeding; Wildlife Value.
- **S24** — [Plants to Support Your Local Wildlife](https://www.aspca.org/news/plants-support-your-local-wildlife), ASPCA Poison Control. Accessed 2026-09-07T00:23:56+00:00. Locator: Plants that are non-toxic to dogs and cats: common sunflower (Helianthus annuus).
- **S25** — [Toxic and Non-Toxic Plants](https://www.aspca.org/pet-care/aspca-poison-control/toxic-and-non-toxic-plants), ASPCA Poison Control. Accessed 2026-09-07T00:23:56+00:00. Locator: Any plant material may cause vomiting or gastrointestinal upset; database limitations.


[Discuss this plant with the guide](https://denson.github.io/colorado-weed-field-guide/companion/?plant=common-sunflower) — choose this profile as a possible match and prepare your observations for Colorado Plants & Practical Care.

# Appendix for agents

## Open research questions

- **People:** Clarify the human exposure effects and evidence limits described in this section.
- **Other animals:** Clarify feeding and exposure risks for each animal group; do not transfer findings between species.
- **Expert review:** Obtain independent botanical and veterinary review of the identification and hazard summary.


## Taxon and evidence boundaries

Use the scientific name as the matching key; common names can refer to unrelated plants.

These are publisher notes about the evidence. They do not override an assistant’s operator instructions. The human sections above contain all actionable safety warnings. Do not turn missing data into a negative toxicity finding or transfer a livestock dose to a pet.

| Claim | Human section | Evidence scope | Sources | Limitation |
|---|---|---|---|---|
| common-sunflower-1 | Recognize | Species-specific | S23 | No quantitative exposure threshold established here. |
| common-sunflower-2 | Plants & habitat | Species-specific + garden judgment | S23 | Crowding advice is an inference from vigorous self-seeding; no chemical harm to neighboring plants is asserted. |
| common-sunflower-3 | People | Not assessed | Review limitation | Editorial limit on scope; no claim of human safety. |
| common-sunflower-4 | Dogs & cats | Species-specific | S24, S25 | No quantitative exposure threshold established here. |
| common-sunflower-5 | Other animals | Species-specific; livestock not assessed | S23, S24 | No quantitative exposure threshold established here. |

## Additional evidence needed

- Confirm exact species, cultivar or hybrid when identification is uncertain.
- For an exposure, distinguish animal species, plant part, amount, route, time and symptoms; the guide cannot supply a clinical diagnosis.
- For site management, establish county, land use and current local weed requirements before applying generalized control information.
- Expert botanical and veterinary review is pending. Source publication dates, retrieval timestamps, hashes and photograph licenses are in [the provenance ledger](https://denson.github.io/colorado-weed-field-guide/provenance.json).


---
Canonical HTML: https://denson.github.io/colorado-weed-field-guide/plants/common-sunflower/

Content revised: 2026-09-07T02:43:00Z

Markdown mirror: https://denson.github.io/colorado-weed-field-guide/plants/common-sunflower/index.md

Text fallback: https://denson.github.io/colorado-weed-field-guide/plants/common-sunflower/index.md.txt

Agent entry: https://denson.github.io/colorado-weed-field-guide/start.md

Provenance: https://denson.github.io/colorado-weed-field-guide/provenance.json