National Invasive Species Awareness Week: Parrot feather

Mary Bohling<bohling@msu.edu>, Michigan Sea Grant, and Bindu Bhakta, Michigan State University Extension - February 24, 2015

Learn more about the parrot feather, an aquatic invasive species in Michigan, and what you can do about it.

National Invasive Species Week 2015 is February 22-28. Invasive species are plants, animals and other organisms that are not traditionally found in a given location (in this case the Great Lakes) and create a negative impact of some kind, whether ecological, economic, social and/or a public health threat.

To help celebrate, each day this week Michigan State University Extension is featuring a different aquatic invasive species that has invaded or has the potential to invade Michigan’s environment. Today’s featured aquatic invasive species is the parrot feather.

Species Name: Parrot feather (Myriophyllumaquaticum)

Description: This aquatic invasive species has both submersed (below water) and emergent (above water) leaves, with stems growing as tall as a foot above water level. The emergent leaves and stems are the most distinctive trait of parrot feather, with a look similar to a small fir tree.

Similar species: Eurasian watermilfoil (Myriophyllumspicatum), which is also invasive in the Great Lakes, and numerous native water milfoils. The two plants are closely related, and while the Eurasian watermilfoil’s leaves do not grow above water level, Virginia DCR recommends consulting a botanist to confirm sightings of parrot feather.

Origin: Parrot feather plants are native to South America along the Amazon River.

How it came to the Great Lakes: The U.S. Geological Survey (USGS) and Michigan Department of Natural Resources (DNR) show that no uncontrolled outbreaks of the plant have been found in the Great Lakes area. However, small outbreaks that were contained have been reported in Indiana and southeast Michigan.

How long it has been here: According to Indiana DNR, parrot feather was first discovered in Meserve Lake in 2006, and Michigan DNR reported finding parrot feather in a southeast Michigan storm water detention pond during 2014.

Extent of range: Parrot feather has a long reach outside of the Great Lakes area, with USGS showing colonies of the plant in most southern states, as well as coming as far north as Connecticut on the East Coast and Washington on the West Coast.

Why it is a problem: From Washington Department of Ecology, “[Parrot feather] can seriously change the physical and chemical characteristics of lakes and streams. Infestations can alter aquatic ecosystems by shading out the algae in the water column that serve as the basis of the aquatic food web. In addition, the plant provides choice mosquito larvae habitat.”

How it is spread: Michigan DNR notes that, while illegal to possess in the state of Michigan, the plant is common for aquariums and water gardens. Once introduced to a system, the plant spreads through fragmentation.

A cool/unusual fact: According to the Washington Department of Ecology, parrot feather plants can only spread in the United States through fragmentation, as all plants in the United States are female. Male plants, though rare, do exist in the native Amazon River habitat but have never been found in the United States.

Management actions/options: Managers have had success in managing small infestations with herbicides and/or manual collection. However, large-scale application of herbicides has had limited success and needs several applications throughout the growing season and repeated over several years to reduce biomass. This is due in large part because the herbicides work well on the plant portions above water, but less so on the below water portions. Several insects feed on parrot feather in its native habitat and are being explored for large scale biological controls elsewhere in the world.

What you can do to help prevent the spread:

Learn how to identify the plant and do not purchase it for aquariums or ponds. Do not dump unwanted aquarium plants into natural areas.

Report it: MDNR, GLANSIS, USGS NAS, and MISIN all accept reports of suspected new introductions. When reporting, it is best to include the date and location of the sighting (with GPS coordinates if possible), a photo, a physical sample and your contact information.

Learn more about how you can help by visiting the Michigan Sea Grant website and Habitattitude.

Invasive Species Resources:

This article was published by Michigan State University Extension. For more information, visit https://extension.msu.edu. To have a digest of information delivered straight to your email inbox, visit https://extension.msu.edu/newsletters. To contact an expert in your area, visit https://extension.msu.edu/experts, or call 888-MSUE4MI (888-678-3464).