The Carlisle Mosquito Online

Friday, September 10, 2010


Glossy Buckthorn

Behold the bitter Buckthorn berry. (Photo by Drew Kissinger)

Invasive species. You hear about them more and more, but what are they and how do you find them? This week is the perfect time to learn to identify one of Carlisle’s most pervasively invasive species: Glossy Buckthorn.

Glossy Buckthorn is a shrub that gets as tall as a small tree. Right now all around Carlisle, every glossy buckthorn plant that is at least 4 feet tall is covered in black berries that are about the size of blueberries – about ¼ inch in diameter. But don’t eat the berries, they smell and taste awful and are poisonous. While the birds and other critters quickly strip our native blueberry bushes, the Glossy Buckthorn berries stay on the bushes for a long time because they taste so bad – you’ll notice many of them are shriveled on the branches. The leaves are oval shaped and have distinct veins that gently curve from the center vein out to the edge of the leaf. Another foolproof way to identify Glossy Buckthorn is to break or cut a main stem – it will have a bright orange center – unlike any of our native shrubs.

A great place to train your eye to identify glossy buckthorn and to observe the destruction caused by this plant is to park at the Cranberry Bog and walk down the Otter Slide Trail about 30 feet. The trail starts about 100 yards from the bog house and follows the stream that flows out of the bog. (See Happy Trails on page 11)

Buckthorn leaves. (Photo by Drew Kissinger)

Glossy Buckthorn grows in profusion on both sides of the trail, and if you look closely, you’ll notice that it is spreading vigorously through the woods. The best way to train your eye is to touch and feel. Pull some leaves off, crush and smell the berries, notice that the stems are covered in beige spots, break a stem and see the orange core. Now look all around this bush and you’ll likely see hundreds of small seedlings spread out all around it, they won’t have berries, but they will have the same leaf shape.

Try to pick out the two native high bush blueberries that are growing on the stream bank (if you are lucky they may still have some late season blueberries hanging on.) Now imagine what this trail would be like if it were lined with high and low-bush blueberry bushes instead of glossy buckthorn. I’ll bet it would be a trail that you’d make a point of visiting mid-summer. You’d definitely see me there picking blueberries.

This is really the answer to the question, “what’s wrong with invasive species?” They invade the landscape, killing off and pushing out our native plant species like blueberries, depriving us and the critters and birds with a delicious and nutritious staple wild food.

Glossy Buckthorn was brought over from Europe and planted as hedgerows. It has long since escaped from cultivation and now has no commercial or food value. Perversely, it is because it has no value to wildlife that it has spread so well. Nothing eats it, so it grows and spreads vigorously.

One of the nicest things about Glossy Buckthorn is that it is one of the easiest of the invasive species in Carlisle to kill. For plants up to about two inches in diameter simply grab onto the main stem and pull the whole plant out of the ground by the roots. The roots of the Buckthorn plant are reddish so you know when you’ve pulled the right one. You can just leave the pulled-up plant on the ground to rot away – it won’t come back. The seeds however, remain viable in the soil for a few years, so new seedlings will keep coming back each spring until all the seeds have sprouted, but are very easy to pull. At my house a kid can earn 2¢ a stem for pulling them!

For plants that are too big to pull without throwing your back out, the Minnesota Department of Natural Resources has a good website that describes each invasive species and mechanical and chemical means to control it. (

Keep in mind that by removing invasive species we are trying to conserve nature in our beautiful town (our water supply included), so be circumspect and careful when using chemicals. Before you do anything in or near wetlands be sure to get approval from the Conservation Commission.

Now that you can identify glossy buckthorn, start to look for it wherever you are in town – you’ll notice it everywhere. ∆

© 2010 The Carlisle Mosquito