giant ragweed

The Irony of Giant Ragweed

From Gene Logsdon
Garden Farm Skills

If you have never been frightened by a weed other than maybe poison ivy, you have not yet faced a battalion of giant ragweeds (Ambrosia trifida) advancing resolutely across your farm. They can grow to a height of 15 feet or more and in a stand so solid as to stop a 200 horsepower corn harvester dead in its tracks. They can overtake a field of knee high corn that has not been sprayed with the proper herbicide and literally choke it to death. In the lexicon of agribusiness, there is no adjective synonymous with ‘vile’ or ‘pernicious’ that has not been used to describe this hated plant of the grain fields. On top of that, it is a major source of irritation for hay fever sufferers. And now on the horizon looms the worst dream of the grain farmer: Giant ragweed is becoming immune to herbicides, particularly glyphosate, the active ingredient of RoundUp. Why the ancient Romans decided to call it ambrosia, that is, gift of the gods,  is one of those mysteries that cries out  to heaven for explanation.

I have a hunch that sheep could explain the mystery if they could talk. They love giant ragweed.  They will go out of their way to eat it, even with a choice of lush fresh clover at hand. Interestingly, while they will nibble on common ragweed, they don’t like it nearly as well.

What is going on here? After spending a long time watching my sheep and reading through the scientific literature, I finally found some clues,  the kind that so often  leads me to wonder if farmers shouldn’t just take a deep breath, step back, and consider the possibility that they are going in the wrong direction.

The seeds of giant ragweed are  47% crude protein. That is very, very high, much higher than any cultivated grain.  What’s more, these seeds, which the plant produces in prodigious amounts, provide, in the words of Roger Wells, a certified wildlife biologist and national habitat coordinator for Quails Unlimited, “the highest amount of metabolizable calories, more even that corn, soybeans, wheat, or any other grain that we know.” What that means is that the seeds are very digestible. Quail or pheasants, in a good stand of giant ragweed will double and triple in population.  (You can find all this and more at on the Internet.) And what is the corn and soybean farmer’s second worse dream? Now you can actually buy giant ragweed seed by the bag if you want to plant some to increase wildlife on your farm.

Primitive Americans must have known something we don’t about giant ragweed. They nurtured it some 2000 years ago. (Giant ragweed is native to America.)  They seem to have quit about 600 years ago and so far anthropologists don’t know why. It is probably because, like modern man, they found maize (corn) easier to handle.

I emailed Dr. Deborah Stinner, a scientist at the Ohio Agricultural Research and Development Center at Wooster, who works with organic grain farmers. Without herbicides, organic farmers are at the mercy of giant ragweed. I was not too surprised that she already knew what I had just learned. “You should come to our meeting tomorrow on this subject,” she emailed back. “And bring your sheep!”  One of the topics under discussion was how to incorporate sheep into a giant ragweed control program.

I did not make it to the meeting and just as well because what I would have said would probably not have set well with corn and soybean farmers.  If quail and pheasants proliferate on giant ragweed, so would chickens it seems to me, as well as sheep. Goats like it too. I know that cows and horses eat it. Seems to me on a garden farm at least, if giant ragweed won’t come to Mohamed then Mohamed should come to giant ragweed. That’s what I would have suggested at the meeting after making sure there were no rotten tomatoes available to throw at me.

But, seriously,  is not giant ragweed worth more scrutiny?  Why did the ancient Romans give ragweed the name, ambrosia?  (Even Thoreau wondered and decided it was because of the golden color of the seeds.) Might the old herbalists have known that the seeds really are a high protein food or a good medicine, and not just for birds? In the sense of homeopathic medicine, which sometimes is effective, perhaps an ingredient in giant ragweed can control the hay fever that the plants seem to cause. Has anyone tried that lately?  Perhaps we are looking at the ultimate irony of over-civilized humankind. We are trying to kill a plant, an ambrosia, that is actually beneficial.

Out of curiosity, I ate a handful of giant ragweed seeds.  I thought sure they would be bitter. Instead, they tasted sort of like wheat bran. I fed some to the chickens while they were penned in the coop. At first they were indifferent, but when I came back an hour later, they had cleaned up all the seeds and foliage I had offered them. What an irony. Here I have been feeding high priced protein supplement to them when they are probably getting all they need from the ragweed growing around the coop. I wonder if that is why they lose interest in eating domestic grains in the summer time.

Perhaps we should be growing fields of giant ragweed and grazing livestock and chickens on it. No mechanical planter, harvester or tanker truck of fuel would be necessary. Just turn farm animals in and let them have at it. Since the plants produce huge amounts of seed, enough would fall to the ground to grow a crop the next year.  Since the seed heads stick up above the foliage, this new “grain” with its 47% very digestible crude protein would also stick up above the snow, making possible the great dream of the northern husbandman: year-round grazing.

I can see a problem if a demand for giant ragweed “grain” increased. I defy John Deere to build a harvester that could thresh its way through a really good stand of the stuff.  Barring something on the order of a helicopter equipped with a vacuum sweeper, this “grain” would have to be harvested manually. But is that really a problem?  It sure doesn’t stop marijuana growers.
See also Gene’s Organic Garden and Small Farm Skills – Hoemanship
Gene and Carol Logsdon have a small-scale experimental farm in Wyandot County, Ohio.
Gene is author of
The Mother of All Arts: Agrarianism and the Creative Impulse (Culture of the Land),
The Last of the Husbandmen: A Novel of Farming Life, and All Flesh Is Grass: Pleasures & Promises Of Pasture Farming

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