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Invasive Species: Herbs

Invasive Herbs

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.

Garlic Mustard

(Alliaria petiolata)

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.

 

More information: Garlic mustard

Giant Hogweed

(Heracleum mantegazzianum)

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.

More information: Giant hogweed

Japanese Chaff Flower

(Achyranthes japonica)

Watch List

Japanese chaff flower is a perennial plant that grows 3-6 feet high with a green, bottle brush-like flower that has no petals.  Leaves are opposite and simple with smooth edges and a pointed tip.

More information: Japanese chaff flower

Purple Loosestrife

(Lythrum salicaria)

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.

More information: Purple loosestrife

Spotted Knapweed

 (Centaurea stoebe)

A bushy, perennial plant growing 2-3 feet with bluish- or grayish-green leaves and thistle-like pinkish-purple flowers.

More information: Spotted knapweed

Wild Parsnip

(Pastinaca sativa)

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.

More information: Wild parsnip