Water hyacinth (Eichhornia crassipes) is a free floating herbaceous invasive species. It can be found floating in freshwater systems, but this species is not tolerant of low temperatures or salty water. Originally this species is from the Amazon basin. This species is commonly for sale by nurseries and growers in Michigan but can easily escape cultivation. Human transportation and boat traffic is a common way this species is dispersed.
Water hyacinth can grow up to 1.5 to 3 feet in height. The leaves are round, smooth, thick, and waxy. The leaf stems have distinctive air bladders that keep the plant floating. The flowers are lavender and grow on a stalk in clusters. There are typically up to 15 flowers on a stalk. Pickerelweed (Pontederia cordata) is similar to this species and is native to Michigan. However, this species has oblong leaves and does not have air bladders on the leaf stem. Michigan State University has a great article about water hyacinth.
Have you seen this species? Report it to us or on the MISIN website or smartphone app! Please include a photo to help with ID verification.
Environmental effect
This species can cause a major problem when it becomes established in a waterbody. Dense mats can form and block out sunlight which hinders native species below the water surface. This can reduce plankton which is a main source of food for fish. When the temperatures are in their ideal range, the biomass can double within a month. When mats become too dense, boats may struggle to travel through it.
Treatments
The is a chemical and non-chemical treatment method for water hyacinth.
NON-CHEMICAL CONTROL METHOD
- Hand pulling: if the patch is not dense, it is easy to remove the floating mat/ plants by hand. Be sure to not leave the remains near water.
CHEMICAL CONTROL METHOD
- Foliar spraying: if there is a well-established patch, spraying the leaves with aquatic safe herbicide can be effective. It is best to apply herbicide in late summer to early fall. When leaves are large, there is a greater surface area to absorb the herbicide.