Humongous Horror Hogweed
Pernicious Persian Parsnip
family: Apiaceae (Umbelliferae)
genus: Heracleum
Species: Mantegazzianum

Introduction and Warning

They are on high alert for an invasion in the Pacific Northwest, as seen by the special URL's set up by Oregon and Washington state agricultural (noxious plant) departments that will be found by search engines looking for Hogweed. This class A weed seeming to be like a mutant version of the Washington State native, Cow Parsnip, Heracleum lanatum, is here generally called Giant Cow Parsnip. It is also related to Colorado's same bovine-named herb, or regular Hogweed, as it is in Europe, Heracleum sphondylium, but the leviathon is most elsewhere known as Giant Hogweed. Obviously the one worth reporting about is this more dangerous and thus more exciting version -- as the ordinary Hogweed. This, uh, garden variety Hogweed, called Meadow Parsnip, also, is similar in structure, but about five times smaller than the fifteen feet its larger cousin boasts is just a harmless wildflower. The 3000 member family Umbelliferae is one that contains other umbrella shaped clustered flowers: Dill, Carrots, Queen Anne's Lace, and Parsley. Though parsnips were mentioned above, the edible variety are the relatives, Pastinaca sativa. And, although most are not such pests as Heracleum mantegazzianum, Conium maculatum was the poisonous Hemlock that Socrates was forced to drink.

Why's Everybody Picking on Me?

Northern Persia in ancient times reported on this plant that is prevalent in the Caucasus Mountains near the Caspian and Black Seas. But, it was during the Victorian era's craze for new exotic plants for their English gardens, that Giant Hogwood joined the Romans, Vikings, Anglo-Saxons, and Normans in invading Britain. It became a favorite of gardeners who wanted a large showy specimen with almost three foot wide flower-heads, (similar to Queen Anne's Lace) five foot incised leaves, and a purple dappled hairy four inch stem, and, of course, the usually twice the height of an adult. It has dry ovoid fruits about quarter of an inch long. It then eventually got loose (two thirds of strangling, mangling, dangling, plants started as ornamentals) and made a happy home on the riparian highways and byways, especially streamsides, yet not before it was touted in gardening books, albeit usually without any warnings. It inevitably dominates any indigenous flora that shares its space by its towering canopy, thirsty roots, and imperious bullying. Home Horticulturalists brought it to other parts of Europe, and the United States. It made the news recently in the Boston Globe, after a Massachusetts woman got blisters cutting down the overgrowth on her new farm, of which complaint originally puzzled her doctor not knowing what she had done a few days before. These sores turned into dark violet scars. This story was then reprinted nationally in the summer of this second year of the new century. In 1999 a Buffalo, New York woman, who got the searing welts after calling about an "unusual species" to Dr. Zander of the Museum of Science (telling her that the plant she discovered could be Cow Parsnip, but warned too late about burns if it was Giant Hogweed.) She could have been spared if she had read the Wildflowers of New York in Color by William K. Chapman who warned it causes "painful burning blisters". It is also a problem in Canada, Maine, Pennsylvania, Michigan and Maryland.

Ignorance is Not Bliss

The U.S. Department of Agriculture, which has made interstate transport of these federal noxious weed listed veggies illegal, admits that the only thing good about this plant, whose watery clear sap contains glucoside and furomarin, a phytophototoxin (i.e. --plant/light/poison) causing hypersensitivity to light radiation and photo-dermatitus, is that it will not chase after you. This herb's blood can blind you if it gets in the eyes. Children find themselves on its bad side after using the large hollow stalks for spears, and worse still, blowguns or flutes. Botanists across the board have no desire to protect this species, but eradicate it thoroughly, but carefully. It is now a threat to wetlands, as well, clogging waterways. Although every year people while learned concerning poison ivys and oaks, nettles, and thistles, get hurt because of their naive unawareness of this plant, British Rail has warning posters to workers near their lines. It's toxicity is most potent at its maturity in mid-summer

More Botanical Factoids

This huge hogweed is a perennial which needs a couple of birthdays before it can put out flowers, which as a monocarpic type plant dies back after its first seedings. But other individuals can keep setting seed from flower crowns, and it can send out shoots from its tubers. It colonizes areas quickly and tenaciously.

Who You Gonna Call?

Get out the Roundup, shovels, scythes, gloves, headgear, coveralls (maybe buy a used CDC protective garment) because if you see this stuff, then you have to get rid of it, but it battles back. Oh, you can start by mowing it down, keep it from seeding and maybe starving it, but ironically it stimulates budding. (Remember the seeds can survive almost a decade). Now the roots, well they are not shallow, long plant with long roots, and they will send out new shoots. Now supposedly cows and pigs will eat the plant without ill effects, and their trampling is damaging to the thing as well. In the case that livestock is not convenient, (and no insect enemy has been found) then using herbacides 2,4 D, TBA, MCPA or Dicamba can kill everything except the roots. Glyphosate (e.g. Roundup) will work if you get on it before flowering early when it is only a two foot tot. The eradicator is warned to not compost this mess, but bag it (I guess they forgot it might grow at the dump) and always do not let the sap get on you, and if so, wash off big time with lots of soap and water, stay out of the sun, maybe call a doctor. The applications must be repeated, and the goal is to get all the roots out, and not let it go to seed.


David Arnold, Boston Globe, July, 2002 (Reprint The Charlotte Observer)

Hog"weed` (?), n. Bot. (a)

A common weed (Ambrosia artemisiaege). See Ambrosia, 3.


In England, the Heracleum Sphondylium.


© Webster 1913.

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