Learn About Invasive Species

Non-Native Invasive Species in Forest County

TERRESTRIAL:

  • Purple Loosestrife
  • Garlic Mustard
  • Wild Parsnip
  • Common Tansy
  • Buckthorn
  • Japanese Knotweed
  • Spotted Knapweed
  • Reed Canary Grass
  • Phragmites
  • Japanese barberry
  • Emerald Ash Borer
  • Earthworms
  • Jumping Worms

AQUATIC (AIS):

  • Eurasian Milfoil
  • Yellow Floating Heart
  • Curly Leaf Pondweed
  • Rusty Crayfish
  • Zebra Mussels
  • Spiny Water Flea
Invasive Species By Lake

View this page to check lakes in your area for invasive species.

Yellow Floating Heart (Nymphoides peltata)

Yellow Floating Heart (Nymphoides peltata)

Yellow floating heart grows in dense mats. It is originally from Eurasia, the Mediterranean, China, India, and Japan.  It is believed to spread from releases from water gardens and the nursery trade.  It reproduces by seeds, stems, or broken off leaves with part of a...

Japanese Knotweed (Polygonum cuspidatum)

Japanese Knotweed (Polygonum cuspidatum)

Japanese knotweed is a semi woody shrub that can reach heights of 8 to 15 feet tall.  The plant resembles bamboo and is often called Japanese bamboo. It originated in Japan and made its way to the United States and Wisconsin as an ornamental plant that people planted...

Purple Loosestrife (Lythrum salicaria)

Purple Loosestrife (Lythrum salicaria)

Purple Loosestrife is a wetland perennial plant that originally arrived here from Europe and Asia.  It was distributed and sold by plant nurseries because of its attractive purple flowers.  People then planted this species in their yards, gardens and lake front...

Spiny and Fishhook Waterfleas

Spiny and Fishhook Waterfleas

This little predatory zooplankton is native to Europe and Asia.  They can grow up to ¾ of an inch in length and eat native Daphnia, which is a food source for many smaller juvenile fish species.  Young fish have difficulties eating the waterflea because the tale often...

Zebra Mussels (Dreissena polymorpha)

Zebra Mussels (Dreissena polymorpha)

Zebra mussels are small bivalve mollusks that are fingernail sized and native the Caspian Sea region of Asia.  These mussels are filter feeders and one mussel can filter one liter of water per day. In the water they feed primarily on phytoplankton, zooplankton, and...

Rusty Crayfish (Orconectes rusticus)

Rusty Crayfish (Orconectes rusticus)

Rusty crayfish are native to streams in the Ohio River Basin states of Ohio, Kentucky, Illinois, Indiana, and Tennessee.  They were introduced to Wisconsin by anglers who used them as fishing bait. These crayfish impact native crayfish populations, aquatic plant...

Curly Leaf Pondweed (Potamogeton crispus)

Curly Leaf Pondweed (Potamogeton crispus)

Curly Leaf Pondweed is one of 80 pondweed species found within the world.  It is native to Eurasia, Africa and Australia.  It was accidently introduced with the common carp in the early 1800’s and made its way to Wisconsin in 1905 with fish imported from Europe. This...