Invasive species can cause real problems

August 2, 2018


I got a very interesting email from a reader recently. I think this column has some of the best-informed people on environmental issues and items that affect us here in Nebraska. I often get emails/calls from folks that have excellent observations and/or questions. This is an example of a gentleman who was very observant of the environment!

The email said he regularly travels I-80 across the state. He had noticed some plants about Mile Marker 254 that he thought was wild dill, until he saw a FOX News story about an invasive plant species called giant hogweed. He thought that might be what he was seeing. That got my attention!

Giant hogweed is part of the carrot family and that seems harmless enough, but it is not a plant we want here! It originally came from south-central Asia and was imported by gardeners who wanted the white flowers of the plant to be a part of their plant menagerie. Like many non-native plants and animals, it got away from the owners and became a problem.

Giant Hogweed got a foothold on the North American continent in Canada and the New England states. According to government agricultural agencies, giant hogweed is moving west across the top tier of states in the U.S. and is now as close as Iowa and Minnesota. That is too close for comfort, folks! The plant has also gotten established in the Pacific Northwest. We are in the middle.

We see the impact of invasive species around us every day! We have phragmite choking the Platte River, zebra mussels and Quagga mussels invading Nebraska waters, Eurasian collared doves fluttering all over town, big head carp in the Missouri, Platte and Elkhorn rivers and they all cause their own unique set of problems.

Giant hogweed it is considered an extreme public health hazard by the U.S. Agriculture Department. The sap of this plant contains toxic chemicals known as furanocoumarins. When these chemicals come into contact with the skin via the plant’s sap and are then exposed to sunlight, they create a condition called phytophotodermatitis, a reddening of the skin often followed by severe blistering and chemical-like burns. The sap can cause temporary, even permanent blindness, if you get it into the eyes.

The effects from contact with giant hogweed can last for several months. Even after the blisters and burns have gone, skin can remain sensitive to light for years. Furanocoumarins are also known to be carcinogenic and cause birth defects.

Giant hogweed can spread quickly because all it takes is a single plant to form a colony. The plants reproduce through both seeds and shoots from their roots, giving the giant hogweed the ability to both populate one local area or spread across a wider range. The seeds remind me of the “stick tights” you get on your clothes when you walk through a field. Giant hogweed seeds will “grab on” to anything that brushes against it and be carried away.

The plant seems to prefer wetter areas like places along streams and rivers. It found in fields, forests and roadside ditches. Giant hogweed can reach 14 feet in height with compound leaves up to 4 feet in width.

Hogweed resembles Queen Anne’s lace, cow parsnip and snow-on-the-mountain, all of which are in Nebraska. After receiving the email, and getting some directions, I went to check it out a few days later. All I found was snow-on-the-mountain (also called snowy spurge) and cow parsnip. That’s a good thing!

If there was giant hogweed there, someone has cut it down and killed it. I’m told that it is relatively easy to eradicate when treated appropriately. You must stay on it though because it takes up to five years to completely eradicate a colony due to regrowth from seeds and roots. I’m hoping it was a case of mistaken identity.

Thanks for being observant!

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