National Invasive Species Awareness Week: Water hyacinth

Part 2 in a series to learn about invasive species and what to do to help protect Michigan and the Great Lakes.

Water hyacinth plants are popular in water ponds and aquariums because of their showy lavender-blue flowers and fast growth. Photo: David Sutton, University of Florida/Center for Aquatic and Invasive Plants. Used with permission.

National Invasive Species Week 2016 is February 21-27. Invasive species are plants, animals, and other organisms that are not traditionally found in a given location (in this case the Great Lakes) AND are having a negative impact of some kind, whether ecological, economic, social, and/or a public health threat.

To help bring awareness to this week, each day Michigan Sea Grant and Michigan State University Extension (MSUE) are featuring two invasive species (one aquatic and one terrestrial species) that have invaded or have the potential to invade Michigan’s environment. Today’s featured aquatic invasive species is the water hyacinth.

Species Name: Water hyacinth (Eichhornia crassipes)

Description: According to the Midwest Invasive Species Information Network this invasive species is a free floating aquatic plant that typically grows 1.5-3ft tall. The leaves are thick and waxy and leaf stems have air bladders that keep the leaves afloat. It has very showy lavender-blue flowers that occur in groups of 8-15 on a single spike. Flowers have 6 petals each with the upper petal having a yellow splotch in the center.

Similar species: The invasive water hyacinth is similar to pickerel weed, which is native to Michigan. However the pickerel weed does not have conspicuous air bladders and does not form dense vegetative mats.

Origin: The water hyacinth is native to the Amazon Basin in South America.

How it came to the Great Lakes: Water hyacinth likely arrived in the Detroit River and Lake St. Clair (tributaries of the Great Lakes) by disposal of unwanted pond/aquarium plants or through recreational boating activities.

How long it has been here: According to the USDA, water hyacinths were introduced in the United States as ornamental pond plants in the 1880’s.

Extent of range: Water hyacinth plants are found in two-thirds of the United States. In Michigan, it has been reported in Livingston, Wayne and Macomb counties and seems particularly persistent in the lower Detroit River/western Lake Erie, where it is unclear if it is dying off during mild winters.

Why it is a problem: The plants form dense vegetative mats that are very effective at blocking sunlight from what had once been open water. This drastically reduces the amount of native algae and plankton in the water, which in turn reduces the food supply for native fish and wildlife. Dead plant material is also constantly being generated by water hyacinths, especially during cold snaps. When the dead plant material is broken down by bacteria and fungi they consume most of the oxygen in the water, leaving none for fish, water bugs or other aquatic animals.

How it is spread: The plant frequently reproduces by fragmentation of stolons and through an adventitious root system and to a lesser extent via seeds.

A cool/unusual fact: Water hyacinth plants reproduce quickly and can double in just two weeks. This means 10 initial plants can multiply to over 600 within 3 months!

Management actions/options: Control of water hyacinth is thought to be fairly easy when detected early in small patches. Control methods include mechanical pulling, biological control, and herbicide.

What you can do to help prevent the spread:

You can prevent the spread of water hyacinths by 1) disposing of water hyacinths purchased for water gardens or aquariums by composting rather than in natural water bodies and 2) practicing the Clean, Drain and Dry method for watercraft prior to moving them between lakes. Watch the video.

This species is currently allowable for sale and possession in Michigan. Please contact the Michigan DNR if these plants are observed outside of cultivation. REPORT IT: If you find this plant in Michigan, remove it if possible, do not put it back in the water and call the MDNR Wildlife Division at 517-641-4903 extension 260.


Read the aquatic series:

Part 1: Introduction

Part 2: Water hyacinth

Part 3: Water chestnut

Part 4: Yellow floating heart

Part 5: Round goby

Part 6: Spiny waterflea

Part 7: Quagga mussel

Read the terrestrial series:

Part 1: Introduction

Part 2: Chinese Yam

Part 3: Kudzu

Part 4: Japanese stilt grass

Part 5: Mile-a-minute weed     

Part 6: Himalayan balsam

Part 7: Asiatic sand sedge

Invasive Species Resources:

Midwest Invasive Species Information Network water hyacinth Fact Sheet,4570,7-153-10370_59996---,00.html

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