The foliage along the trails at Fox Island tends to blend together, and for many people (like me) it’s hard to spot the differences between plants. But if you look closely, you’ll notice that there is one common plant that has a unique color pattern on the leaves: while the tops of the leaves usually have the familiar green, the undersides of the leaves have a contrasting silvery hue.
This plant is the invasive autumn olive (Elaeagnus umbellate). It was introduced from Asia to North America almost two hundred years ago. The origin of the plant, when combined with that silvery hue of both the leaves and the unripened berries, explains why autumn olive is also commonly known as Japanese silverberry.
How will you know if you are looking at autumn olive? First look for the silvery undersides of the leaves. In late spring, autumn olive produces clustered white flowers that are favored by many of the pollinators at Fox Island. The fruits, which turn from silver to red when they ripen, are an important food source for many animals at Fox Island. The popularity of the flowers and seeds means autumn olive can be found almost anywhere.
Autumn olive is a major food sources for many animals and provides shelter for many others. It also houses nitrogen-fixing bacteria in its roots, which allows it to grow in soil that many native plants cannot grow in. Combine all of these factors together, and it’s not hard to see why autumn olive has become so widespread.
Autumn olive grows thick. It was originally planted in many areas to create natural hedge barriers. Unfortunately it’s really good at this, and in many Indiana ecosystems, it grows so densely that it hinders native plant growth.
In Indiana and in other parts of North America, autumn olive has been classified as a noxious weed. It’s very hard to remove. If the plant is small enough you might be able to pull it, and this may be enough, provided you get the entire plant (including the roots). But if it is big enough, then like many of the invasive plant species at Fox Island, simply cutting autumn olive down isn’t enough to eradicate it. The roots need to be chemically treated to ensure the plant cannot grow back.
You are most likely to see autumn olive at Fox Island along trails, roads, and at forest edges. You are especially likely to find it at the edges of both the east and west prairie habitats and along the lake road. Have you seen autumn olive in Fox Island? Comment below and let us know when and where you saw it. And contact the park staff to see how you can get involved in removing it!
Nature Conservancy. (2019). Journey with Nature: Autumn Olive. Retrieved from https://www.nature.org/en-us/about-us/where-we-work/united-states/indiana/stories-in-indiana/autumn-olive/
Ormiston, J. (2019, April). Personal interview.
Penn State Extension. (2019). Autumn Olive. Retrieved from http://extension.psu.edu/autumn-olive
Weston Nurseries. (2013). Autumn Olive – A Challenging Species. Retrieved from http://www.westonnurseries.com/autumn-olive-a-challenging-species/