While there are a variety of different invasive species found within the Jackson, Lenawee and Washtenaw County region, we are primarily focused on the following species:

Japanese stiltgrass (Microstegium vimineum)
Identification:

• 2-3 feet tall
• Resembles small, delicate bamboo
• Asymmetrical leaves are pale green and lance-shaped

Habitat: This annual grass is generally associated with moist, rich soils. It survives at varying levels of soil acidity and can tolerate lighting from full sun exposure to deep shade. Common establishment locations include moist woodlands, roadside ditches, early successional fields, and stream banks.
Native Range: China, Japan, Korea, Malaysia, and India
U.S. Distribution: Japanese stiltgrass has been introduced to the southeast region of the U.S. as far north as New York and as far west as Texas.
Local Concern: Stiltgrass spreads opportunistically after a disturbance. It forms dense patches and displace native understory vegetation as the patches expand.
​Other Common Names: Nepalese browntop, Asian stilt grass, Nepal, microstegium, eulalia, Mary’s grass, annual jewgrass, Chinese packing grass
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Parrot feather (Myriophyllum aquaticum)
*Prohibited in Michigan

Identification:

• Spikes of stiff, feathery leaves grow in whorls of 4-6
• Bright green upper stem emerges up to 1 foot above water
• Small, inconspicuous white flowers where leaves attach to the section of stem above water
• Stems and submerged leaves may be tinted reddish
• All U.S. plants are female, spread via fragmentation

Habitat: Occurs in slow-moving fresh water habitats such as tributaries, canals, ponds, and lakes. It shows preference for high nutrient environments with plenty of light.
​Native Range: South America
U.S. Distribution: Parrot feather can be found in at least 26 states, including those along the Eastern, Southern, and Western coasts.
​Local Concern: This invasive milfoil plant threatens native aquatic species through competition. It will often form dense mats which provides habitat for mosquito larvae and can impede boats.

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Japanese knotweed (Fallopia japonica)
​*Prohibited in Michigan

Identification:

• Perennial, herbaceous shrub that can grow from 3-10 feet high
• Hollow stalks are persistent through winter, looks similar to bamboo
• Stems have a fine white coating that rubs off easily
• Flowers arranged in spikes near the end of the stem are small, numerous, and creamy white in color
• Flowers bloom in August and September in Michigan

Habitat: Japanese knotweed can be found along roadsides, wetlands, wet depression, woodland edges, and stream or river banks. Full sun conditions are preferable, although this plant can tolerate some shade and a wide range of soil and moisture conditions.
Native Range: Asia
U.S. Distribution: Japanese knotweed has been introduced to most of the contiguous U.S. Florida, Alabama, Texas, New Mexico, Arizona, Nevada, Wyoming, and North Dakota are the exceptions.
Local Concern: Japanese knotweed grows very aggressively in disturbed areas. It excludes native plants by light limitation, nutrient cycling alterations, and allelopathy (releasing toxic or inhibiting chemicals to suppress the growth of potential competitor plant species).

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Giant Hogweed (Heracleum mantegazzianum)
*Prohibited in Michigan

Identification:

• White flowers in an umbrella-shaped cluster up to 2.5 feet across
• Plant is 7 to 14 feet tall
• Stems are green with purple splotches and visible, coarse, white hairs
• Leaves are up to 5 feet wide, lobed and deeply incised

Habitat: Prefers open, slightly moist areas but can be found in a variety of habitats.
Native Range: Asia
Local Concern: Giant hogweed has the potential to harm humans.  Its sap can cause a severe skin reaction known as photo-dermatitis or photo-sensitivity and damage to the eyes.  The skin becomes sensitive to sunlight and may blister when exposed.  If you think you may have come in contact with giant hogweed sap, wash the exposed area immediately, keep the exposed area out of the sunlight and seek medical care.
Look-alikes:  Many other plants, including cow parsnip, wild parsnip, angelica and Queen Anne’s lace are often misidentified as giant hogweed.  Take the time to review similar plants before reporting this species. 

Phragmites (Phragmites australis)
*Ristricted in Michigan

Identification:

• Warm-season perennial grass with a rigid, hollow stem
• Height ranges from 6-13 feet
• Leaves are flat, smooth, and green to grayish-green
• Flowers grow as dense branched clusters on the end of each stem that are open and feathery at maturity

​Habitat: Common reed, sometimes called phragmites, is often found in ditches, swales, wetlands, and on stream and pond banks.
Native Range: Phragmites australis is native to North America and commonly found around the world. One strain of this species is thought to be exotic or hybrid and is quickly replacing the native strain in many areas.
Local Concern: Phragmites can be difficult to walk through (for humans and wildlife) and often obstructs landowner views because of its ability to grow in tall, dense patches. The exotic strain can reduce native fish and wildlife populations, block out native salt marsh vegetation, and can be a fire danger for nearby residents.

Species information taken from State of Michigan Invasive Species Page (click here)