Home Grown 270 September 7, 2004

I just saw an article in the paper about Giant Hogweed. Is this noxious weed in our county? How do I identify this plant? I have seen a couple of things that look like it already.

Relax; your kingdom is safe. Giant hogweed has been found in a few places in the state. The places that it has been found have been mostly in people’s gardens because they planted it. Except in two places, it hasn’t escaped to the fields and forests to endanger the native people. It has been found in Ingham, Jackson, Branch and Gogebic Counties. Other than 50 plants in a Gogebic garden and several hundred feet of plants along a roadside in Branch County, it has been one or two planted so the gardener can brag about having the biggest plant in the county. This plant is worrisome because of its effects on people touching it. It causes blistering and burning when people come in contact with the plant sap. Giant Hogweed is unique because of its size. At this time of the year, it is 12 to 15 feet tall. It has green compound leaves that are deeply incised. Leaves are almost five feet across. The stem can be anywhere from two to four inches in diameter and reddish purple. The flower looks like a mammoth Queen Ann’s Lace. It has a white flat-topped flower described as an umbel. It’s two and a half feet across. At this time of the year, the flower head will have become a seed head with large brown seeds. Leaf stems are a blotchy purple and green. The plant has coarse white hairs. If these are broken, clear sap is exuded onto the unlucky person. When the sap is on a person’s skin and comes in contact with sunlight, the skin burns and blisters. It will scar to a permanent purple to black color. If you get sap in your eyes, you can become permanently blind. Before you go crazy with worry, remember the size, 12 to 15 feet tall with leaves almost five feet across. This is a massive plant that is hard to miss. We have several smaller native plants that might be mistaken for this, like Cow Parsnip. It might get five or six feet tall. Golden Alexander might get four or five feet tall. Queen Ann’s Lace might get to three or four feet tall. Just remember: size does matter, especially in the world of Giant Hogweed.



I was out mowing and got about five stings from some kind of insect because I think I ran over them in the ground. They looked like bees or wasps. I tried to spray the area with bug spray immediately and got stung again. What are they and how do I get rid of them?

Welcome to the evil world of Yellow Jackets. They are wasps with an attitude. When you run over their home and they get even. Bees can only sting you once and they are finished. But each wasp can sting you multiple times and will if there is an opportunity. Your target is wasps and not 
bees and your weapon is Sevin Garden Dust. This is a pesticide with the chemical name of arbaryl. It is relatively easy to locate in a store that sells other pesticides. To rid yourself of your attack squadron, you need to become a Backyard Commando. When it is dark outside in the evening, slip into stealth mode and sneak up to their location. Liberally dust the entrance-exit holes with a coating of Sevin Garden Dust. Toss a shovel full of moist soil over the dusted area and retreat silently into the night. The next day, check the area where the soil was tossed. If you see flying wasps or holes in the soil, go for a repeat mission that evening. In most cases, one treatment is enough. Wasps have no night vision and all return to the nest in the evening. They are also very sensitive to vibration. Just look at what that mower started. Remember the code words: stealth, commando and shadow ops. Get out there and neutralize with extreme prejudice.

Gretchen Voyle, MSU Extension-Livingston County Horticulture
Agent 517/546-3950

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