--- { "id": "large-crabgrass", "name": "Large crabgrass", "scientific": "Digitaria sanguinalis", "category": "invasive", "status": "Common introduced weed · not on state Lists A/B/C", "status_sources": [ "C-floristic-2020", "CO-rules-2025" ], "warning": "Fast seed production in thin lawns", "warning_tone": "caution", "aliases": [ "crabgrass", "hairy crabgrass" ], "taxonomy_note": "One source photograph is labeled Digitaria sanguinalis subsp. pectiniformis; that label is preserved, without asserting its occurrence in Colorado.", "source_ids": [ "C-floristic-2020", "CO-rules-2025", "N-digitaria-sanguinalis", "C-descriptions", "S27" ], "description": "Large crabgrass: Fast seed production in thin lawns. Identification and evidence for Colorado readers.", "claim_evidence": [ { "label": "Identification", "sources": [ "N-digitaria-sanguinalis", "C-descriptions" ], "scope": "Species-specific", "note": "", "id": "large-crabgrass-1" }, { "label": "People", "sources": [], "scope": "Review limitation", "note": "", "id": "large-crabgrass-2" }, { "label": "Dogs & cats", "sources": [], "scope": "Review limitation", "note": "", "id": "large-crabgrass-3" }, { "label": "Other animals", "sources": [], "scope": "Review limitation", "note": "", "id": "large-crabgrass-4" }, { "label": "Plants & habitat", "sources": [ "N-digitaria-sanguinalis" ], "scope": "Species-specific", "note": "", "id": "large-crabgrass-5" }, { "label": "Management & timing", "sources": [ "N-digitaria-sanguinalis" ], "scope": "Species-specific", "note": "", "id": "large-crabgrass-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": "People", "question": "Clarify the human exposure effects and evidence limits described in this section.", "related_claim_ids": [ "large-crabgrass-2" ] }, { "area": "Dogs & cats", "question": "Find species-specific dog and cat exposure evidence; do not infer safety from missing reports.", "related_claim_ids": [ "large-crabgrass-3" ] }, { "area": "Other animals", "question": "Clarify feeding and exposure risks for each animal group; do not transfer findings between species.", "related_claim_ids": [ "large-crabgrass-4" ] }, { "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 49; Digitaria sanguinalis", "basis": "Included in the 2020 statewide flora assessment. This is not a current county abundance survey.", "source_taxon": "Digitaria sanguinalis" }, "source": "content/plants/large-crabgrass.md" } --- # Large crabgrass *Digitaria sanguinalis* **Common 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) > **Fast seed production in thin lawns.** [Exposure help](https://denson.github.io/colorado-weed-field-guide/safety/). **Identification caveat:** One source photograph is labeled Digitaria sanguinalis subsp. pectiniformis; that label is preserved, without asserting its occurrence in Colorado. ## Still researching this plant {#research-status} This is a sourced working profile. Evidence is incomplete for **People, 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. ![Large crabgrass: a low spreading grass clump with green leaf blades and long radiating stems on bare soil.](https://denson.github.io/colorado-weed-field-guide/assets/photos/coverage-garden-photos-digitaria-sanguinalis-01-02-habit.jpg) **habit** — A low spreading grass clump with green leaf blades and long radiating stems on bare soil. Photo: Rasbak; [CC BY-SA 3.0](https://creativecommons.org/licenses/by-sa/3.0/); [source record](https://commons.wikimedia.org/wiki/File:Harig_vingergras_plant_(Digitaria_sanguinalis).jpg); [original image](https://upload.wikimedia.org/wikipedia/commons/f/fa/Harig_vingergras_plant_%28Digitaria_sanguinalis%29.jpg). Source page scientific identification plus visual morphology review of the selected photograph. This is a source-identified reference image, not a specimen-based taxonomic determination. Source-identified D. sanguinalis. The inflorescence photo is explicitly labeled D. sanguinalis subsp. pectiniformis and retains that source wording. Similar crabgrasses require detailed hair, ligule, and spikelet characters for an unknown specimen; these references do not determine a Colorado specimen’s subspecies. Wikimedia server-resized derivative, reduced from the original; no crop, color change, upscaling, or generative editing. Gallery display preserves the full image; catalog preview may use a CSS crop. ![Large crabgrass: several photographed leaf bases showing membranous ligules and conspicuous long hairs.](https://denson.github.io/colorado-weed-field-guide/assets/photos/coverage-garden-photos-digitaria-sanguinalis-01-03-leaf-collar.jpg) **leaf-collar** — Several photographed leaf bases showing membranous ligules and conspicuous long hairs. Photo: Rasbak; [CC BY-SA 3.0](https://creativecommons.org/licenses/by-sa/3.0/); [source record](https://commons.wikimedia.org/wiki/File:Harig_vingergras_ligula_(Digitaria_sanguinalis).jpg); [original image](https://upload.wikimedia.org/wikipedia/commons/6/6e/Harig_vingergras_ligula_%28Digitaria_sanguinalis%29.jpg). Source page scientific identification plus visual morphology review of the selected photograph. This is a source-identified reference image, not a specimen-based taxonomic determination. Source-identified D. sanguinalis. The inflorescence photo is explicitly labeled D. sanguinalis subsp. pectiniformis and retains that source wording. Similar crabgrasses require detailed hair, ligule, and spikelet characters for an unknown specimen; these references do not determine a Colorado specimen’s subspecies. Wikimedia server-resized derivative, reduced from the original; no crop, color change, upscaling, or generative editing. Gallery display preserves the full image; catalog preview may use a CSS crop. ![Large crabgrass: several slender finger-like flower spikes radiate from the top of a grass stem against a blue sky.](https://denson.github.io/colorado-weed-field-guide/assets/photos/coverage-garden-photos-digitaria-sanguinalis-01-11-inflorescence.jpg) **inflorescence** — Several slender finger-like flower spikes radiate from the top of a grass stem against a blue sky. Photo: Stefan.lefnaer; [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0); [source record](https://commons.wikimedia.org/wiki/File:Digitaria_sanguinalis_subsp._pectiniformis_sl18.jpg); [original image](https://upload.wikimedia.org/wikipedia/commons/4/42/Digitaria_sanguinalis_subsp._pectiniformis_sl18.jpg). Source page scientific identification plus visual morphology review of the selected photograph. This is a source-identified reference image, not a specimen-based taxonomic determination. Source-identified D. sanguinalis. The inflorescence photo is explicitly labeled D. sanguinalis subsp. pectiniformis and retains that source wording. Similar crabgrasses require detailed hair, ligule, and spikelet characters for an unknown specimen; these references do not determine a Colorado specimen’s subspecies. Wikimedia server-resized derivative, reduced from the original; no crop, color change, upscaling, or generative editing. Gallery display preserves the full image; catalog preview may use a CSS crop. ## Identification A summer annual grass with sprawling stems that root at joints, hairy leaf bases and fingerlike seedhead branches. This profile covers large crabgrass; the common name also includes other Digitaria species. [N-digitaria-sanguinalis](https://plants.ces.ncsu.edu/plants/digitaria-sanguinalis/) [C-descriptions](https://extension.colostate.edu/resource/weed-descriptions/) ## People The reviewed sources do not establish species-specific ingestion effects or a safe exposure amount for people. Missing evidence does not establish safety. ## Dogs & cats The reviewed sources do not establish species-specific ingestion effects or a safe exposure amount for dogs or cats. Missing evidence does not establish safety. ## 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. ## Plants & habitat It colonizes disturbed soil and lawns. Its ability to root along spreading stems helps it occupy bare patches. [N-digitaria-sanguinalis](https://plants.ces.ncsu.edu/plants/digitaria-sanguinalis/) ## Management & timing Remove seedlings before extensive rooting and seed production. Mulch garden beds and maintain dense turf; frost kills the annual plant, but surviving seeds can start another generation. [N-digitaria-sanguinalis](https://plants.ces.ncsu.edu/plants/digitaria-sanguinalis/) ## 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-digitaria-sanguinalis** — [Digitaria sanguinalis](https://plants.ces.ncsu.edu/plants/digitaria-sanguinalis/), NC State Extension. Accessed 2026-09-07T02:23:11+00:00. Locator: Description, identification attributes and plant problems; toxicity section where present. - **C-descriptions** — [Weed descriptions](https://extension.colostate.edu/resource/weed-descriptions/), Colorado State University Extension. Accessed 2026-09-07T00:24:02+00:00. Locator: Species entries. - **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=large-crabgrass) — 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 49; Digitaria sanguinalis. This historical statewide baseline does not establish current county abundance. ## Open research questions - **People:** Clarify the human exposure effects and evidence limits described in this section. - **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 Match the scientific name and synonyms, not the common name alone. 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 | |---|---|---|---|---| | large-crabgrass-1 | Identification | Species-specific | N-digitaria-sanguinalis, C-descriptions | No quantitative safe exposure established here. | | large-crabgrass-2 | People | Review limitation | Review limitation | No quantitative safe exposure established here. | | large-crabgrass-3 | Dogs & cats | Review limitation | Review limitation | No quantitative safe exposure established here. | | large-crabgrass-4 | Other animals | Review limitation | Review limitation | No quantitative safe exposure established here. | | large-crabgrass-5 | Plants & habitat | Species-specific | N-digitaria-sanguinalis | No quantitative safe exposure established here. | | large-crabgrass-6 | Management & timing | Species-specific | N-digitaria-sanguinalis | 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/large-crabgrass/ Content revised: 2026-09-07T02:46:00Z Markdown mirror: https://denson.github.io/colorado-weed-field-guide/plants/large-crabgrass/index.md Text fallback: https://denson.github.io/colorado-weed-field-guide/plants/large-crabgrass/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