Living the buckthorn and bittersweet life

Sometimes ignorance is bliss. I have a faint (ever-so-faint) recollection of the carefree joy I used to feel while hiking in the woods. “Aren’t these woods pretty?” I would think. “Look at all those pretty wildflowers along the roadside. Isn’t life grand?” My bliss was permanently disrupted, though, when I took my first ecology class in college and learned about invasive species. Now, it’s hard to go for a hike without silently cataloguing every plant I see along the way that doesn’t belong.

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So pretty, right? WRONG! These pink, tubular flowers are called Grecian foxglove. It’s an invasive species that has just begun to appear in Minnesota, mostly in a few locations in Afton and Stillwater Township. Don’t touch it with bare hands, as the plant contains a chemical compound that can cause heart problems for some people.

Invasive species include plants, animals and even fungus that are introduced to ecosystems outside of their natural territories, spread, and cause harm. Some well-known local examples include buckthorn, zebra mussels, and Japanese beetles. Biologists consider invasive species to be one of the leading threats to biodiversity worldwide. According to the National Wildlife Federation, 42% of threatened and endangered species are at risk due to invasive species. In the scholarly journal Nature Communications, researchers from the U.S. and U.K. warn that “one-sixth of the global land surface is highly vulnerable to invasion, including substantial areas in developing economies and biodiversity hotspots.”[1]

Here in Minnesota, we’re seeing the impacts of invasive species in our treasured woods and lakes. One common invasive – buckthorn – has taken over thousands of acres of woodlands around the Twin Cities metro. This invasive shrub from Europe chokes out native flowers and shrubs that provide food and habitat for birds and wildlife, and prevents native tree saplings from taking root and growing. In our area, buckthorn threatens the long term survival of oaks, maples and other hardwood trees, and can also contribute to erosion and water pollution.

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The bark of buckthorn is smooth with little horizontal lines.
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Female buckthorn also grow blackish-purple berries.

Oriental bittersweet is another non-native, invasive plant that has just begun to take hold in Washington County. It is a woody vine that grows by winding around trees, girdling their trunks as they grow. It is highly invasive in forests in the eastern U.S. but is only found in a few locations in Minnesota so far. Minnesota Department of Agriculture hopes to stop it from spreading further and has added the plant to its Prohibited Noxious Weed (Eradicate List), which means that landowners are required to take action to eradicate it on their properties.

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The Oriental bittersweet vine wraps around trees, girdling them as it grows.

This month, Washington Conservation District is hosting two free workshops about buckthorn and oriental bittersweet. Learn from professionals on how to identify invasive plants from native plants, understand the life cycle of woody plants, and choose the best methods to control woody plants on your property. The workshops will begin with a short presentation, followed by a hike into the woods to see the plants and post-treatment results. Choose from the following dates and locations:

Register at For questions, contact Lauren Haydon at 651-330-8220 x.24.

[1] Regan Early, Bethany A. Bradley, Jeffrey S. Dukes, Joshua J. Lawler, Julian D. Olden, Dana M. Blumenthal, Patrick Gonzalez, Edwin D. Grosholz, Ines Ibañez, Luke P. Miller, Cascade J. B. Sorte & Andrew J. Tatem (2016) Global threats from invasive alien species in the twenty-first century and national response capacities.

Nature Communications, 7. Article number: 12485