Giant salvinia

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

Salvinia molesta

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.

Floating mats harm aquatic habitat. Exposure help.

Identification caveat: Several floating ferns look similar. Close inspection of leaf hairs is needed; no photo alone establishes 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

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

Salvinia molesta: Close view of floating, folded green leaves with textured upper surfaces. — **floating foliage** — Close view of floating, folded green leaves with textured upper surfaces.
Ixitixel · CC BY-SA 3.0
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. Salvinia species can be similar. The selected images follow source identifications; the diagnostic joined hair tips are not resolved clearly in every view.
Wikimedia server-resized derivative; no local crop, colour change, or generative editing. Gallery display preserves the full image; the catalog preview uses a CSS crop.

Salvinia molesta: Floating folded leaves with water droplets; the source describes this as a photograph focus-stacked from 20 exposures. — **leaf surface** — Floating folded leaves with water droplets; the source describes this as a photograph focus-stacked from 20 exposures.
Krzysztof Ziarnek, Kenraiz · 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. Salvinia species can be similar. The selected images follow source identifications; the diagnostic joined hair tips are not resolved clearly in every view.
Wikimedia server-resized derivative; no local crop, colour change, or generative editing. Source photographer describes the original as focus-stacked from 20 exposures. Gallery display preserves the full image; the catalog preview uses a CSS crop.

Salvinia molesta: Lake Wilson in Hawaii covered by a dense salvinia mat, with a vehicle and boat on the near shore. — **infestation** — Lake Wilson in Hawaii covered by a dense salvinia mat, with a vehicle and boat on the near shore.
Nani Shimakuku, U.S. Army Corps of Engineers · Public domain
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. Salvinia species can be similar. The selected images follow source identifications; the diagnostic joined hair tips are not resolved clearly in every view.
Wikimedia server-resized derivative; no local crop, colour change, or generative editing. Gallery display preserves the full image; the catalog preview uses a CSS crop.

Recognize

A floating fern with paired surface fronds and submerged, root-like fronds. Magnification reveals characteristic joined, eggbeater-shaped hairs. N-salvinia-molesta

Plants & habitat

Thick mats restrict light and oxygen, clog water intakes and obstruct recreation. Do not introduce it into ponds or discard aquarium material outdoors. N-salvinia-molesta

People

Dense surface mats obstruct boating and swimming; this is a water-access hazard rather than a demonstrated ingestion syndrome. N-salvinia-molesta

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

Habitat effects include reduced oxygen and harm to fish and aquatic plants. Direct livestock toxicity is not established here. N-salvinia-molesta

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-salvinia-molesta — salvinia molesta — 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.