Species that are not native and also have the potential to harm human health or to harm natural, agricultural or silvicultural resources can be listed as prohibited or restricted by the State of Michigan. If a species is prohibited or restricted, it is unlawful to possess, introduce, import, sell or offer that species for sale as a live organism, except under certain circumstances.
Butterbur is a flowering plant that grows to 6 feet tall, with simple, round to heart-shaped leaves that are 1-2 feet across.
- Garlic Mustard
Garlic mustard is a 1 to 4 foot plant with serrated leaves and clusters of tiny, white, 4-petaled flowers that bloom in early spring. It smells like garlic when crushed.
- Giant Hogweed
Prohibited in Michigan
Giant Hogweed is a plant that has the potential to harm humans. The plant grows 7-14 feet tall and has white flowers in an umbrella-shaped cluster up to 2.5 feet across. The stems are green with purple splotches and visible coarse, white hairs. The leaves are up to 5 feet wide, lobed and deeply incised.
- Himalayan Balsam
Himalayan Balsam grows 3-6 feet tall and has purple/red stems that are smooth and hollow. There are 5-10 flowers on each stem and the flowers have 5 petals that are purple, pink, or white in color. The fruit capsules explode when ripe and touched.
- Purple Loosestrife
Restricted in Michigan
Purple Loosestrife is a perennial herb with a woody square stem covered in downy hair. It varies in height from 4 - 10 feet. It has leaves that are arranged in pairs or whorls and magenta flower spikes with 5 - 7 petals per flower that are present for most of the summer.
- Spotted Knapweed
A bushy, perennial plant growing 2-3 feet with bluish- or grayish-green leaves and thistle-like pinkish-purple flowers.
- Wild Parsnip
Wild parsnip is a single stemmed plant that grows to 5 feet tall. Yellowish green flowers form umbrella-shaped clusters 4 to 8 inches across.