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Invasive Species: Herbs
Invasive Herbs
Butterbur
(Petasites hybridus)
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
(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.
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.
Himalayan Balsam
(Impatiens glandulifera)
Watch List
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.
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.
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.
Spotted Knapweed
(Centaurea stoebe)
A bushy, perennial plant growing 2-3 feet with bluish- or grayish-green leaves and thistle-like pinkish-purple flowers.
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.