Invasive Species in Michigan

Phragmites australis 

Grows in damp/wet ground and can grow to 8-12 ft tall. Typically seen in wetlands next to cattails or in drainage ditches along roadsides. Phragmites grow in dense thickets and have an underground network of roots meaning they spread rapidly and are difficult to remove. 

Elaeagnus Umbelleta 

This shrub can grow up to 20ft tall, produces bright red berries and occasionally small thorns characterized by the "wavey" leaves and smooth grey bark. Green leaves emerge in early spring and remain until late fall, sometimes into early winter.  

Rosa multiflora

A variety of rose originating from Asia that has shooting stems with recurved thorns. The stems can grow 10-16 ft tall with vine-like tendencies. Can be confused with blackberry and raspberry bushes but can be differentiated by color. Multiflora Rose has green stems, while blackberry and raspberry have purple stems.  

Lonicera maackii 

Can grow up to 20 feet tall and has light-furrowed bark. Produces red berries and flowers in late spring/early summer. Originally planted as an ornamental plant to form hedgerows, but due to the rapidly spreading nature of the plant, it soon became a nuisance.  

Rhamnaceae sp.

A deciduous shrub that has thorns approximately 1-2 inches in length. The dark-colored berries, though poisonous to humans and other mammals, contain seeds that are dispersed by birds. It spreads rapidly and is incredibly hearty growing up to 10ft tall.  There are two common buckthorn species in Michigan: Common Buckthorn (Rhamnus cathartica) and Glossy [Alder] Buckthorn (Rhamnus frangula)

Robinia pseudoacaea

These trees can grow up to 100ft tall. They are shade intolerant and grow in young woodlands and lots of direct sunlight in disturbed areas. Younger trees will usually have spines, but mature trees will typically lack spines. The bark is  black/gray with a reddish-orange tinge.  

Berberis thumbergii

A small bush ornamental bush that is green, green/blue, or reddish purple. The branches have dark brown bark with little spines. Like most invasive species it is avoided by wildlife and replaces native plant species.  

Celastrus orbiculata 

This vine grows in thickets on bushes on the tops of trees.  Oriental Bittersweet will spread throughout large areas of the forest choking out trees in the overstory and smaller bushes and saplings in the understory. It produces bright red and orange berries to disperse its seeds.  

Cirsium arvense  

This thistle likes lots of sunlight and groundwater. It has a purple "spike ball" flower and sharp spiny leaves that distinguish it from the Spotted Knapweed. Due to its ability to adapt quickly and its underground network of roots, it is extremely invasive.  

Lythrum salicaria 

Often found in wet areas (ditches, marshes, lakesides, ect.), this plant consists of one large woody stem holding many flowers. Each flower will come to seed which contributes to how quickly this plant can spread. Because it is a food source for many insects, some of which can be harmful, it can attract many insects.  

Centaurea maculosa   

This weed is typically seen in open fields, prairies, shore banks, and roadsides. The large taproot allows this plant to survive in harsh conditions. The purple flowers turn to seed in late summer and are dispersed by wind, much like dandelions.