Yellow Iris

Yellow Iris is Unfortunately Thriving on Cranberry Lake

Yellow Iris

In 2014, the Vilas County Invasive Species Coordinator expressed concern and enlisted the help of ERCLA in addressing yet another invasive species present on the Eagle River Chain – Yellow Iris.

Yellow iris is non-native in the United States, and is spreading throughout the country. This good-looking wetland plant has been transplanted into gardens all over the world. Yellow iris colonizes into large numbers, forming very dense stands, outcompeting other plants.

It was brought to the United States as an ornamental plant in the early 1900’s. It is regulated by the state of Wisconsin, and classified as a restricted plant. However, it continues to be sold over the Internet. Yellow iris is a robust plant, 3-6 feet tall, with beautiful bright yellow flowers that bloom from May to July. The plant spreads by seeds and by underground stems known as rhizomes that send out new shoots. Stands of yellow iris develop thick mats that can connect several hundred plants which can alter wildlife habitat and species diversity. Fragments of rhizomes that break off can form new plants. All parts of this plant are poisonous, which results in lowered wildlife foodsources.

The spread of yellow iris can be controlled by digging out the plant, diligently cutting it back, removing seed heads, or limiting activities near the plants such as mowing and weed whacking.  A project on the effectiveness of cutting back this plant is underway on Cranberry Lake.

Each summer a core group of volunteers survey the entire Chain and notes the locations with GPS coordinates.

A map showing the location of Yellow Iris on the Eagle River Chain in 2016 is available. Click here to view the map.

We are in need of volunteers to monitor the Yellow Iris, so please consider helping. You need not be a year 'round resident. Click here to volunteer.

Additional information can be found at the following website:

Yellow Iris