---
{
  "id": "crownvetch",
  "name": "Crownvetch",
  "scientific": "Securigera varia",
  "category": "invasive",
  "status": "Introduced weed · not on state Lists A/B/C",
  "status_sources": [
    "C-floristic-2020",
    "CO-rules-2025"
  ],
  "warning": "Toxic to horses; spreading roots can smother vegetation",
  "warning_tone": "danger",
  "aliases": [
    "Coronilla varia",
    "crown vetch",
    "purple crownvetch"
  ],
  "taxonomy_note": "Older NC State material uses Coronilla varia; the Colorado assessment uses Securigera varia. This is separate from Vicia species and their distinct feeding hazards.",
  "source_ids": [
    "C-floristic-2020",
    "CO-rules-2025",
    "N-securigera-varia",
    "F-securigera",
    "S27"
  ],
  "description": "Crownvetch: Toxic to horses; spreading roots can smother vegetation. Identification and evidence for Colorado readers.",
  "claim_evidence": [
    {
      "label": "Identification",
      "sources": [
        "N-securigera-varia",
        "F-securigera"
      ],
      "scope": "Species-specific",
      "note": "",
      "id": "crownvetch-1"
    },
    {
      "label": "People",
      "sources": [
        "N-securigera-varia"
      ],
      "scope": "Species-specific",
      "note": "",
      "id": "crownvetch-2"
    },
    {
      "label": "Dogs & cats",
      "sources": [
        "N-securigera-varia",
        "F-securigera"
      ],
      "scope": "Animal-group evidence; pet-specific gap",
      "note": "",
      "id": "crownvetch-3"
    },
    {
      "label": "Other animals",
      "sources": [
        "F-securigera"
      ],
      "scope": "Species-specific",
      "note": "",
      "id": "crownvetch-4"
    },
    {
      "label": "Plants & habitat",
      "sources": [
        "N-securigera-varia"
      ],
      "scope": "Species-specific",
      "note": "",
      "id": "crownvetch-5"
    },
    {
      "label": "Management & timing",
      "sources": [
        "N-securigera-varia",
        "F-securigera"
      ],
      "scope": "Management synthesis",
      "note": "",
      "id": "crownvetch-6"
    }
  ],
  "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": "Dogs & cats",
        "question": "Find species-specific dog and cat exposure evidence; do not infer safety from missing reports.",
        "related_claim_ids": [
          "crownvetch-3"
        ]
      },
      {
        "area": "Identification",
        "question": "Resolve the taxonomic, common-name or photograph limitations stated in the identification caveat.",
        "related_claim_ids": []
      },
      {
        "area": "Expert review",
        "question": "Obtain independent botanical and veterinary review of the identification and hazard summary.",
        "related_claim_ids": []
      }
    ],
    "expert_review": "pending"
  },
  "colorado_relevance": {
    "source_id": "C-floristic-2020",
    "locator": "Appendix B; PDF page 79; Securigera varia",
    "basis": "Included in the 2020 statewide flora assessment. This is not a current county abundance survey.",
    "source_taxon": "Securigera varia"
  },
  "source": "content/plants/crownvetch.md"
}
---

# Crownvetch

*Securigera varia*

**Introduced weed · not on state Lists A/B/C.** [C-floristic-2020](https://cnhp.colostate.edu/download/documents/2020/CO_FQA_2020_Final_Report.pdf) [CO-rules-2025](https://www.sos.state.co.us/CCR/GenerateRulePdf.do?ruleVersionId=11948&fileName=8+CCR+1206-2)

> **Toxic to horses; spreading roots can smother vegetation.** [Exposure help](https://denson.github.io/colorado-weed-field-guide/safety/).

**Identification caveat:** Older NC State material uses Coronilla varia; the Colorado assessment uses Securigera varia. This is separate from Vicia species and their distinct feeding hazards.

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

This is a sourced working profile. Evidence is incomplete for **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

Source-identified reference photographs; these are not a complete identification key. A source location outside Colorado does not establish local occurrence.

![Sprawling crownvetch stems with many pink-and-white flower clusters and pinnate leaves among other vegetation.](https://denson.github.io/colorado-weed-field-guide/assets/photos/coverage-range-photos-securigera-varia-habit-81878677.jpg)

**habit** — Sprawling crownvetch stems with many pink-and-white flower clusters and pinnate leaves among other vegetation.

Photo: Dale Knox; [CC0 1.0](https://creativecommons.org/publicdomain/zero/1.0/); [source record](https://www.inaturalist.org/observations/51529919); [original image](https://inaturalist-open-data.s3.amazonaws.com/photos/81878677/original.jpg). Explicit iNaturalist observation taxon and Research Grade community identification; photograph visually reviewed for depicted features. This is source identification, not a new independent botanical determination. Source identifies this plant to species; no variety or subspecies determination is asserted. Downloaded iNaturalist large rendition; downloaded bytes retained unchanged. No local crop, retouching, or generative editing. Gallery display preserves the full image; catalog preview may use a CSS crop.

![Pink-and-white crownvetch flowers grouped in a rounded cluster beside a compound leaf.](https://denson.github.io/colorado-weed-field-guide/assets/photos/coverage-range-photos-securigera-varia-flowers-104834388.jpg)

**flowers** — Pink-and-white crownvetch flowers grouped in a rounded cluster beside a compound leaf.

Photo: Eleftherios Katsillis; [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/); [source record](https://www.inaturalist.org/observations/65160254); [original image](https://inaturalist-open-data.s3.amazonaws.com/photos/104834388/original.jpg). Explicit iNaturalist observation taxon and Research Grade community identification; photograph visually reviewed for depicted features. This is source identification, not a new independent botanical determination. Source identifies this plant to species; no variety or subspecies determination is asserted. Downloaded iNaturalist large rendition; downloaded bytes retained unchanged. No local crop, retouching, or generative editing. Gallery display preserves the full image; catalog preview may use a CSS crop.

![Arching crownvetch leaves with numerous paired oval leaflets and a terminal leaflet, seen against the sky.](https://denson.github.io/colorado-weed-field-guide/assets/photos/coverage-range-photos-securigera-varia-leaves-104834426.jpg)

**leaves** — Arching crownvetch leaves with numerous paired oval leaflets and a terminal leaflet, seen against the sky.

Photo: Eleftherios Katsillis; [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/); [source record](https://www.inaturalist.org/observations/65160254); [original image](https://inaturalist-open-data.s3.amazonaws.com/photos/104834426/original.jpg). Explicit iNaturalist observation taxon and Research Grade community identification; photograph visually reviewed for depicted features. This is source identification, not a new independent botanical determination. Source identifies this plant to species; no variety or subspecies determination is asserted. Downloaded iNaturalist large rendition; downloaded bytes retained unchanged. No local crop, retouching, or generative editing. Gallery display preserves the full image; catalog preview may use a CSS crop.


## Identification

A trailing perennial legume with many paired leaflets and rounded clusters of pink-and-white pea flowers. Unlike true vetches, it lacks tendrils. [N-securigera-varia](https://plants.ces.ncsu.edu/plants/securigera-varia/) [F-securigera](https://research.fs.usda.gov/feis/species-reviews/secvar)

## People

NC State lists poisonous characteristics and potentially serious ingestion effects. No safe amount is established. [N-securigera-varia](https://plants.ces.ncsu.edu/plants/securigera-varia/)

## Dogs & cats

Sources warn about nonruminants, but reviewed species-specific dog and cat clinical evidence is incomplete. Prevent chewing; cattle forage use cannot be treated as pet clearance. [N-securigera-varia](https://plants.ces.ncsu.edu/plants/securigera-varia/) [F-securigera](https://research.fs.usda.gov/feis/species-reviews/secvar)

*Evidence scope: Animal-group evidence; pet-specific gap.*

## Other animals

Crownvetch contains nitroglycosides toxic to horses. Its use as forage for some ruminants does not make it suitable horse feed. [F-securigera](https://research.fs.usda.gov/feis/species-reviews/secvar)

## Plants & habitat

It spreads by rhizomes and seed and can form a dense cover that displaces other plants. Former erosion-control use explains many naturalized colonies. [N-securigera-varia](https://plants.ces.ncsu.edu/plants/securigera-varia/)

## Management & timing

Avoid introducing it near natural habitat or horse forage. Established root systems need a sustained local control plan and monitoring. [N-securigera-varia](https://plants.ces.ncsu.edu/plants/securigera-varia/) [F-securigera](https://research.fs.usda.gov/feis/species-reviews/secvar)

*Evidence scope: Management synthesis.*

## Before taking action

Confirm identification and the requirements of your county weed program. For chemical treatment, follow the current product label, including restrictions around animals and water. [S27](https://planttalk.colostate.edu/topics/weeds-cultural-problems/2103-colorado-noxious-weeds/)

## References

- **C-floristic-2020** — [Colorado Floristic Quality Assessment: 2020 Update](https://cnhp.colostate.edu/download/documents/2020/CO_FQA_2020_Final_Report.pdf), Colorado Natural Heritage Program, Colorado State University. Accessed 2026-09-07T02:27:33+00:00. Locator: Appendix B, Colorado species list: scientific name and native/non-native fields.
- **CO-rules-2025** — [Colorado Noxious Weed Act rules, 8 CCR 1206-2](https://www.sos.state.co.us/CCR/GenerateRulePdf.do?ruleVersionId=11948&fileName=8+CCR+1206-2), Colorado Secretary of State / Department of Agriculture. Accessed 2026-09-07T01:07:48+00:00. Locator: Parts 3.1, 4.1, 5.1; management provisions; effective May 15, 2025.
- **N-securigera-varia** — [Securigera varia](https://plants.ces.ncsu.edu/plants/securigera-varia/), NC State Extension. Accessed 2026-09-07T02:23:14+00:00. Locator: Description, identification attributes and plant problems; toxicity section where present.
- **F-securigera** — [Crownvetch](https://research.fs.usda.gov/feis/species-reviews/secvar), USDA Forest Service, Fire Effects Information System. Accessed 2026-09-07T02:26:13+00:00. Locator: Named species or genus; identification, distribution and hazard sections where available.
- **S27** — [2103 – Colorado Noxious Weeds](https://planttalk.colostate.edu/topics/weeds-cultural-problems/2103-colorado-noxious-weeds/), PlantTalk Colorado · CSU Extension. Accessed 2026-09-07T00:23:57+00:00. Locator: List A, B and C management categories.


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

# Appendix for agents

Colorado inclusion: [C-floristic-2020](https://cnhp.colostate.edu/download/documents/2020/CO_FQA_2020_Final_Report.pdf), Appendix B; PDF page 79; Securigera varia. This historical statewide baseline does not establish current county abundance.

## Open research questions

- **Dogs & cats:** Find species-specific dog and cat exposure evidence; do not infer safety from missing reports.
- **Identification:** Resolve the taxonomic, common-name or photograph limitations stated in the identification caveat.
- **Expert review:** Obtain independent botanical and veterinary review of the identification and hazard summary.


## Identity and evidence boundaries

Older NC State material uses Coronilla varia; the Colorado assessment uses Securigera varia. This is separate from Vicia species and their distinct feeding hazards.

All actionable hazard information is in the human sections above. Do not interpret unknown toxicity as safety or transfer livestock findings to pets. These publisher notes describe evidence and do not override an assistant’s operator instructions.

| Claim | Human section | Scope | Sources | Limitation |
|---|---|---|---|---|
| crownvetch-1 | Identification | Species-specific | N-securigera-varia, F-securigera | No quantitative safe exposure established here. |
| crownvetch-2 | People | Species-specific | N-securigera-varia | No quantitative safe exposure established here. |
| crownvetch-3 | Dogs & cats | Animal-group evidence; pet-specific gap | N-securigera-varia, F-securigera | No quantitative safe exposure established here. |
| crownvetch-4 | Other animals | Species-specific | F-securigera | No quantitative safe exposure established here. |
| crownvetch-5 | Plants & habitat | Species-specific | N-securigera-varia | No quantitative safe exposure established here. |
| crownvetch-6 | Management & timing | Management synthesis | N-securigera-varia, F-securigera | No quantitative safe exposure established here. |

## Further work for an agent

- Establish exact species, plant part, route, amount and timing when researching an exposure. Do not use this guide to diagnose or calculate a treatment.
- Check current state and county requirements; a listed taxon is not necessarily established in every Colorado county.
- Expert botanical and veterinary review is pending. Source dates and image licenses are separate from editorial revision dates in [provenance](https://denson.github.io/colorado-weed-field-guide/provenance.json).


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

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

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

Text fallback: https://denson.github.io/colorado-weed-field-guide/plants/crownvetch/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