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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.
Chaff Flower (formerly Japanese chaff flower)
(Achyranthes japonica)
Watch List
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.
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.
Lesser Celandine
(Ficaria verna)
Watch list
Lesser celandine is an invasive spring ephemeral plant that can spread to form thick mats in floodplain forests and along trails, crowding out important native vegetation, and creating opportunities for erosion when it goes completely dormant by late spring.
Purple Jewelweed (formerly Himalayan balsam)
(Impatiens glandulifera)
Watch List
Purple jewelweed 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
(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.