The Mission of the Yellowstone County Weed Department is to assist the public, private, and other government agencies to manage and control existing noxious weed infestations as well as to prevent new invasive species from infesting Yellowstone County.

ParrotfeatherMyriophyllum aquaticum

Photo from Montana Weed Control Association

Aquatic

Leaf

Leaf

Leaf

Patch

Infestation

Photos from Montana Weed Control Association

Attribute	Information
Toxicity	Non-toxic.
Control	Aquatic herbicide. Contact your County Weed District or local Applicator for more information.
Habitat	Lake and pond edges, drainage canals, slow moving waterways and rivers.
Root	Extensive, shallow root system.
Leaf Shape	Feather-like leaves.
Lifespan	Perennial; two years or longer.
Priority 3 Weed	Not a noxious weed, but a regulated plant; potential for significant negative economic and ecological impacts.
Similar Looking Plants	Eurasian watermilfoil, Northern watermilfoil, Coontail and water marigold.
Important Information	Commonly sold for aquaria and aquatic gardens; it has escaped to become invasive in ponds and other calm water bodies. Can reproduce from roots and plant fragments.