An identifier of Giant Hogweed is the 15-foot height of the plants. Another identifier of Giant Hogweed is the two-to-four-inch hollow stem, which is red to purple. This same stem has little bristles.
This serious weed has been pushing its way through Ohio.
One of the challenging things about this weed is that it is easily confused with other relatives. But right now, as we pull weeds out of our gardens, we identify poisonous plants and dress appropriately, wearing long sleeves and gloves.
This hogweed is even worse than poison ivy or poison hemlock. Giant Hogweed can cause a problem called phytophotodermatitis. The compound in the sap is called furocoumarin.
What happens is that the sap inside the plant that gets on your skin can cause your pigment to change. Then the skin becomes extremely sensitive to the sun’s rays.
Exposed areas on your skin can swell and blister even cause a permanent scar. Get some of this sap in your eyes, and you can suffer from temporary or possibly permanent blindness.
A compound from the shorter cousin of Poison Hemlock was used by ancient Greeks to execute criminals or political prisoners.
At church last week, a friend asked me, “Are there any good ways of killing Giant Hogweed?”
I replied, “I’ll take a look.”
I return to topics that I have covered in the past with new solutions as they come up. I try to help my readers with the current treatments for perennial problems until the problem is eliminated or new solutions are presented.
Giant Hogweed or Heracleum mantegazzianum is native to the Caucasus Mountains in Europe.
Hogweed has made it on the national “Noxious Weed List.” Noxious weeds can harm you or your livestock. It is not native and takes over a very fertile area.
Snap Dragons and Giant Hogweed are biennials that take two years to develop.
What I find kind of scary about this plant is that one plant of Giant Hogweed can produce as many as 70,000 seeds. Seeds can be dormant for up to five years or more.
This plant looks a lot like Queen Anne’s Lace on steroids, which makes sense in that Giant Hogweed is a member of the Apiaceae family, or the carrot family.
So, one of the keys to identifying these plants is that you see a flower and leaf structure at times during the year, like Queen Anne’s Lace, but the leaves vary as they grow older. One of the other key identifiers is the stem has purple areas and white hair.
Giant Hogweed was imported from Europe in 1917 and kept in some upscale gardens in New York. Landscape designers find this 15-foot-tall plant interesting because of the variety of shapes in the leaves and a little purple in the stem.
Giant Hogweed is cultivated in Europe. Bottom leaves on Giant Hogweed grow up to five feet in size towards the end of the season in moist, fertile soil.
The best way to destroy these toxic weeds is to mow well before seeds set.
I suppose that within a few years of mowing these plants faithfully, there would be no seeds out there to grow. Regular ditch mowing will go a long way toward controlling these noxious, poisonous weeds.
I commend all the local road crews for the mowing.
Several chemicals can kill these weeds. The reason for naming this plant Giant Hogweed is that hogs find this plant very edible.
Wow, right?
In Europe, where they cultivate Giant Hogweed, Spider Mites, Scale Insects, Fungus Gnats, Mealybugs, Aphids, Whiteflies, and Weevils attack this plant. Soil solarization with heavy black plastic can also work.
Sheep, goats, and cattle graze on Giant Hogweed. Pigs will uproot the plant when feeding. Light pigment animals have greater problems with the sap.
Remember that if you try killing this plant, you need rubber gloves, long sleeves, and long pants.
Depending on the season, to prevent sap from getting in your eyes, wear a mask. We all need to use caution in working with this plant.
I hope you have a nice stroll through your garden this week.
If you have a problem, you can email me at ericlarson546@yahoo.com.