--- { "id": "cutleaf-teasel", "name": "Cutleaf teasel", "scientific": "Dipsacus laciniatus", "category": "invasive", "status": "Colorado noxious weed · List B — Stop the spread", "status_sources": [ "CO-rules-2025" ], "warning": "Prickly stands can displace native vegetation", "warning_tone": "caution", "aliases": [ "cut-leaved teasel" ], "taxonomy_note": "Common teasel usually has unlobed leaves and lavender flowers. Flower color alone does not establish the species.", "source_ids": [ "CO-rules-2025", "F-teasels", "S27", "Fremont-list-definitions" ], "description": "Cutleaf teasel: Prickly stands can displace native vegetation. Identification and evidence for Colorado readers.", "claim_evidence": [ { "label": "Recognize", "sources": [ "F-teasels" ], "scope": "Species-specific", "note": "", "id": "cutleaf-teasel-1" }, { "label": "Plants & habitat", "sources": [ "F-teasels" ], "scope": "Species-specific", "note": "", "id": "cutleaf-teasel-2" }, { "label": "People", "sources": [ "F-teasels" ], "scope": "Physical-risk inference", "note": "", "id": "cutleaf-teasel-3" }, { "label": "Dogs & cats", "sources": [ "F-teasels" ], "scope": "Physical-risk inference; ingestion evidence gap", "note": "", "id": "cutleaf-teasel-4" }, { "label": "Other animals", "sources": [], "scope": "Review limitation", "note": "", "id": "cutleaf-teasel-5" }, { "id": "cutleaf-teasel-list-meaning", "label": "State-list meaning", "sources": [ "Fremont-list-definitions" ], "scope": "Colorado management-category definition; species classification retains its original status sources", "note": "Plain-language editorial label for a management category; not a toxicity or danger rating.", "reviewed": "2026-09-07" } ], "noxious_class": "B", "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": [ "cutleaf-teasel-4" ] }, { "area": "Other animals", "question": "Clarify feeding and exposure risks for each animal group; do not transfer findings between species.", "related_claim_ids": [ "cutleaf-teasel-5" ] }, { "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" }, "noxious_class_label": "B — Stop the spread", "source": "content/plants/cutleaf-teasel.md" } --- # Cutleaf teasel *Dipsacus laciniatus* **Colorado noxious weed · List B — Stop the spread.** [CO-rules-2025](https://www.sos.state.co.us/CCR/GenerateRulePdf.do?ruleVersionId=11948&fileName=8+CCR+1206-2) Established in some areas. Requirements vary by location: eradication, containment or suppression to stop further spread. This is a management category, separate from danger ratings. [Category source](https://fremontcountyco.gov/weed-control/weed-identification) · [What the lists mean](https://denson.github.io/colorado-weed-field-guide/safety/#weed-lists). > **Prickly stands can displace native vegetation.** [Exposure help](https://denson.github.io/colorado-weed-field-guide/safety/). **Identification caveat:** Common teasel usually has unlobed leaves and lavender flowers. Flower color alone does not establish the species. ## Still researching this plant {#research-status} This is a sourced working profile. Evidence is incomplete for **Dogs & cats, Other animals**. 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. ![Dry oval teasel head on a prickly stalk, with rigid bracts surrounding the head.](https://denson.github.io/colorado-weed-field-guide/assets/photos/list-bc-photos-dipsacus-laciniatus-01.jpg) **dry head** — Dry oval teasel head on a prickly stalk, with rigid bracts surrounding the head. Photo: Alexander Klink; [CC BY 3.0](https://creativecommons.org/licenses/by/3.0); [source record](https://commons.wikimedia.org/wiki/File:Dipsacus_laciniatus_L.jpg); [original image](https://upload.wikimedia.org/wikipedia/commons/4/40/Dipsacus_laciniatus_L.jpg). Source-identified photograph with visual consistency check Dipsacus laciniatus L. Source labeling and visible consistency checked; not an independent specimen determination. Wikimedia-generated thumbnail rescaling only; downloaded bytes unchanged. Gallery display preserves the full image; the catalog preview uses a CSS crop. ![Opposite, deeply cut leaves around a teasel stem, with an oval flowering head behind them.](https://denson.github.io/colorado-weed-field-guide/assets/photos/list-bc-photos-dipsacus-laciniatus-03.jpg) **leaves and stem** — Opposite, deeply cut leaves around a teasel stem, with an oval flowering head behind them. Photo: Alex Abair; [CC BY 4.0](https://creativecommons.org/licenses/by/4.0); [source record](https://commons.wikimedia.org/wiki/File:Dipsacus_laciniatus_554862782.jpg); [original image](https://upload.wikimedia.org/wikipedia/commons/f/fb/Dipsacus_laciniatus_554862782.jpg). Source-identified photograph with visual consistency check Cutleaf teasel ( Dipsacus laciniatus ) in the United States Source labeling and visible consistency checked; not an independent specimen determination. Wikimedia-generated thumbnail rescaling only; downloaded bytes unchanged. Gallery display preserves the full image; the catalog preview uses a CSS crop. ![Close view of small white flowers on an oval teasel head among pointed bracts, with a 20 mm scale.](https://denson.github.io/colorado-weed-field-guide/assets/photos/list-bc-photos-dipsacus-laciniatus-06.jpg) **flowers** — Close view of small white flowers on an oval teasel head among pointed bracts, with a 20 mm scale. Photo: Stefan.lefnaer; [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0); [source record](https://commons.wikimedia.org/wiki/File:Dipsacus_laciniatus_sl21.jpg); [original image](https://upload.wikimedia.org/wikipedia/commons/7/7b/Dipsacus_laciniatus_sl21.jpg). Source-identified photograph with visual consistency check Capitulum (detail) Taxonym: Dipsacus laciniatus ss Fischer et al. EfÖLS 2008 ISBN 978-3-85474-187-9 Location: Marchfeldkanal near Groß-Jedlersdorf, Wien-Floridsdorf - ca. 160 m a.s.l. Habitat: fallow land Source labeling and visible consistency checked; not an independent specimen determination. Wikimedia-generated thumbnail rescaling only; downloaded bytes unchanged. Gallery display preserves the full image; the catalog preview uses a CSS crop. ## Recognize Deeply cut, opposite leaves clasp the stem; generally white flowers open on prickly, elongated heads. [F-teasels](https://research.fs.usda.gov/feis/species-reviews/dipspp) ## Plants & habitat Reported near Denver. Dense stands can threaten meadow and wetland vegetation; impacts vary among sites. [F-teasels](https://research.fs.usda.gov/feis/species-reviews/dipspp) ## People Prickles on stems and heads make unprotected handling a puncture concern. [F-teasels](https://research.fs.usda.gov/feis/species-reviews/dipspp) *Evidence scope: Physical-risk inference.* ## Dogs & cats Prickly plants present a contact hazard; the reviewed source does not establish pet ingestion effects. [F-teasels](https://research.fs.usda.gov/feis/species-reviews/dipspp) *Evidence scope: Physical-risk inference; ingestion evidence gap.* ## Other animals The reviewed sources do not establish species-specific ingestion effects or a safe exposure amount for livestock. Missing evidence does not establish safety. ## 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 - **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. - **F-teasels** — [Fuller’s and cutleaf teasel](https://research.fs.usda.gov/feis/species-reviews/dipspp), USDA Forest Service. Accessed 2026-09-07T01:34:00+00:00. Locator: Species descriptions, occurrence and hazard sections; food preparation and treatment instructions not adopted. - **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=cutleaf-teasel) — choose this profile as a possible match and prepare your observations for Colorado Plants & Practical Care. # Appendix for agents ## Open research questions - **Dogs & cats:** Find species-specific dog and cat exposure evidence; do not infer safety from missing reports. - **Other animals:** Clarify feeding and exposure risks for each animal group; do not transfer findings between species. - **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 Common teasel usually has unlobed leaves and lavender flowers. Flower color alone does not establish the species. 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 | |---|---|---|---|---| | cutleaf-teasel-1 | Recognize | Species-specific | F-teasels | No quantitative safe exposure established here. | | cutleaf-teasel-2 | Plants & habitat | Species-specific | F-teasels | No quantitative safe exposure established here. | | cutleaf-teasel-3 | People | Physical-risk inference | F-teasels | No quantitative safe exposure established here. | | cutleaf-teasel-4 | Dogs & cats | Physical-risk inference; ingestion evidence gap | F-teasels | No quantitative safe exposure established here. | | cutleaf-teasel-5 | Other animals | Review limitation | Review limitation | 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). ## State-list label provenance The label “B — Stop the spread” is this guide’s plain-language summary of [Fremont County’s Colorado noxious-weed definitions](https://fremontcountyco.gov/weed-control/weed-identification) [Fremont-list-definitions]. The letter and species assignment retain the status sources above. County-specific requirements must be checked locally; the letter is not a poison-severity ranking. --- Canonical HTML: https://denson.github.io/colorado-weed-field-guide/plants/cutleaf-teasel/ Content revised: 2026-09-07T03:50:00Z Markdown mirror: https://denson.github.io/colorado-weed-field-guide/plants/cutleaf-teasel/index.md Text fallback: https://denson.github.io/colorado-weed-field-guide/plants/cutleaf-teasel/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