Giant reed

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

Arundo donax

Colorado noxious weed · List A — Eradicate. CO-rules-2025

Uncommon in Colorado. All populations are designated for eradication statewide. This is a management category, separate from danger ratings. Category source · What the lists mean.

Dense stands displace riparian plants. Exposure help.

Identification caveat: This is a grass, not a true bamboo. Variegated garden cultivars are not evidence of an exemption from the listed species.

Still researching this plant

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.

Arundo donax: A dense stand of tall, jointed canes and long leaves near water. — **stand** — A dense stand of tall, jointed canes and long leaves near water.
zebedeugalinha · CC BY 4.0
Photo source and identification
Original record · Original image
Source scientific identification plus visual morphology review of the selected photograph. This is a source-identified reference image, not a specimen-based taxonomic determination.
iNaturalist large server-resized image; no local crop, colour change, or generative editing. Gallery display preserves the full image; the catalog preview uses a CSS crop.

Arundo donax: Lower and middle portions of a dense cane stand, with visible upright stems and leaf sheaths. — **stems** — Lower and middle portions of a dense cane stand, with visible upright stems and leaf sheaths.
zebedeugalinha · CC BY 4.0
Photo source and identification
Original record · Original image
Source scientific identification plus visual morphology review of the selected photograph. This is a source-identified reference image, not a specimen-based taxonomic determination.
iNaturalist large server-resized image; no local crop, colour change, or generative editing. Gallery display preserves the full image; the catalog preview uses a CSS crop.

Arundo donax: A leafy cane showing broad, arching blades attached at successive nodes. — **foliage and nodes** — A leafy cane showing broad, arching blades attached at successive nodes.
zebedeugalinha · CC BY 4.0
Photo source and identification
Original record · Original image
Source scientific identification plus visual morphology review of the selected photograph. This is a source-identified reference image, not a specimen-based taxonomic determination.
iNaturalist large server-resized image; no local crop, colour change, or generative editing. Gallery display preserves the full image; the catalog preview uses a CSS crop.

Recognize

A very tall, bamboo-like grass with broad clasping leaves and large, feathery flower plumes. N-arundo-donax

Plants & habitat

Rapid rhizome growth crowds out other plants. Stem nodes can root; moving cut material can spread an infestation. N-arundo-donax

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.

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

This is a statewide eradication priority. Contact your county weed program promptly for identification and an approved management and disposal plan. CO-rules-2025

References

CO-rules-2025 — Colorado Noxious Weed Act rules, 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-arundo-donax — arundo donax — Plant Toolbox, NC State Extension. Accessed 2026-09-07T01:04:51+00:00. Locator: Description; Attributes; Problems; Poisonous to Humans.
S27 — 2103 – Colorado Noxious Weeds, PlantTalk Colorado · CSU Extension. Accessed 2026-09-07T00:23:57+00:00. Locator: List A, B and C management categories.

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