Common teasel

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

Dipsacus fullonum

Colorado noxious weed · List B — Stop the spread. J-teasel

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 · What the lists mean.

Prickly heads; prolific seed spread. Native status, garden use and noxious-weed class are separate from toxicity. Exposure help.

Identification caveat: The Colorado county designation is for Dipsacus spp. This page illustrates source-identified D. fullonum; cutleaf teasel, D. laciniatus, requires a separate identification.

Still researching this plant

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

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.

Dipsacus fullonum: Tall erect teasel stem with opposite leaves and branching upper flower-head stalks. — **habit** — Tall erect teasel stem with opposite leaves and branching upper flower-head stalks.
Isidre blanc · CC BY-SA 4.0
Photo source and identification
Original record · Original image
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. Common teasel is also recorded as Dipsacus sylvestris. Do not transfer the identification to cutleaf teasel (D. laciniatus) or cultivated fuller's teasel (D. sativus) without checking diagnostic features.
Wikimedia server-resized derivative; no crop, color change, or generative editing. Gallery display preserves the full image; the catalog preview uses a CSS crop.

Dipsacus fullonum: Egg-shaped prickly head with a horizontal band of lilac flowers and long curved basal bracts. — **flower** — Egg-shaped prickly head with a horizontal band of lilac flowers and long curved basal bracts.
Isidre blanc · CC BY-SA 4.0
Photo source and identification
Original record · Original image
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. Common teasel is also recorded as Dipsacus sylvestris. Do not transfer the identification to cutleaf teasel (D. laciniatus) or cultivated fuller's teasel (D. sativus) without checking diagnostic features.
Wikimedia server-resized derivative; no crop, color change, or generative editing. Gallery display preserves the full image; the catalog preview uses a CSS crop.

Dipsacus fullonum: Opposite leaves join around a prickly stem to form a water-holding cup. — **leaf-stem** — Opposite leaves join around a prickly stem to form a water-holding cup.
Björn Appel · CC BY-SA 3.0
Photo source and identification
Original record · Original image
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. Common teasel is also recorded as Dipsacus sylvestris. Do not transfer the identification to cutleaf teasel (D. laciniatus) or cultivated fuller's teasel (D. sativus) without checking diagnostic features.
Wikimedia server-resized derivative; no crop, color change, or generative editing. Gallery display preserves the full image; the catalog preview uses a CSS crop.

Recognize

Prickly oval heads above stems with paired leaves that form cups. The county’s teasel account describes purple or white flowers and curved bracts. J-teasel

Evidence scope: Dipsacus group; source-identified photo examples.

Plants & habitat

Introduced teasels spread by seed in disturbed areas and ditch banks. Remove rosettes or flowering heads before seed dispersal and monitor for new plants. J-teasel

Evidence scope: Dipsacus group.

People

Prickly heads and stems present a handling hazard; gloves are a practical precaution. J-teasel

Evidence scope: Physical-risk inference.

Dogs & cats

Prickly dried material may injure paws or mouths. Chemical toxicity has not been established here. J-teasel

Evidence scope: Physical-risk inference; toxicity gap.

Other animals

Species-specific ingestion effects and exposure thresholds were not established in the reviewed sources. This is an evidence gap, not proof of safety.

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

J-teasel — Teasel, Jefferson County, Colorado. Accessed 2026-09-07T00:27:26+00:00. Locator: Description, impacts, Colorado list designation, management.

Content revised 2026-09-07 03:50:00Z · Source checks dated separately in the references.