Common Ragweed

sEPTEMBER, AT home, PiTTsBuRGH, AND remembering a FiELD iN

Hudson valley, new york

In some of these chapters, I feel like I'm giving a used-car-salesman introduction to a yard plant, trying to convince you that it's good enough for a test drive at least. I'm not going to try to persuade you to like ragweed. In fact, common ragweed gives me flashbacks. So feel free to continue right on hating ragweed as you sneeze your way through this chapter.

Ragweed is more often found by a roadside than in a lawn. Certainly, ragweed would happily grow in any bare patch of lawn, if given half a chance and a month without mowing. In most areas, in September, as Emily approaches her harvest-time birthday, ragweed is releasing pollen—if you aren't allergic to grass pollen in spring, ragweed pollen is the next plant likely to make you miserable.

Several sibling weeds are called by the same genus name as common ragweed (Ambrosia artemisiifolia), which has ragged leaves resembling marigolds in shape. Giant ragweed (Ambrosia trifida), true to its Latin and English names, grows easily to basketball player height and bears three-pointed leaves, and few would contradict you in comparing the leaf to a devilish trident. Both common and giant ragweed are among the many allergens in the family, whereas mugwort (Ambrosia vulgaris), though also weedy, is also celebrated for its herbal properties and appealing smell.

Now for the story behind my flashbacks. The cornfield I was cultivating for research in the Hudson Valley of New York during grad school was incredibly infested with ragweed. In some weed science experiments, this would be ideal. A field that is uniformly infested with a particular weed is considered a perfect field for testing the effectiveness of different herbicides on that weed. Weed scientists will cultivate fields of weeds for a couple of years, sometimes even treating the field with herbicides that are chosen especially because they will kill weeds other than the one they are cultivating. Then, once a thick population of the weed of interest is built up, scientists test herbicides on that weed. There were other methods for building up weed populations as well, depending on the experiment and on the weed biology. Sometimes weed scientists buy seeds of a particular weed and spread it at the beginning of the growing season. In my first weed science experiment, I actually grew weeds in the greenhouse and transplanted them into my soybean field so I could watch the weeds' effects on the two soybean varieties of interest.

All this effort may seem ridiculous for plants that obviously grow just fine without our help, thank you very much, or even despite our best efforts to kill them. However, the goal of all these machinations is to create uniform stands of weeds across the field, so that the weed control options can be evaluated under comparable conditions. In that field in the Hudson Valley that summer, I was studying herbicide treatments for quackgrass, a weed that can produce nutritious hay for cattle or sheep but is also invasive, especially in the sandy soils common to the Hudson Valley region. I was not trying to study ragweed, and its presence was entirely unwelcome.

The field manager, Paul, had taken steps to help prevent weeds other than my quackgrass and had applied another herbicide, which we knew was useless against quackgrass, to the corn when it was planted. This was an herbicide that needed a bit of rain to help the chemical soak into the soil and kill the germinating ragweed seeds, thereby accomplishing what's called "herbicide activation." But we had a dry summer, and unfortunately, the herbicide did not get acti vated in time. The ragweed sprouted right through that dry soil and the layer of herbicide. Paul had intentions of getting back to spray the ragweed with a different herbicide a couple of weeks later, but by the time he finished all the other essential experimental planting and spraying, the corn was too tall to drive the spray truck through without damaging it. Paul was very apologetic, and I knew he was really sorry, because he didn't have time for hand-pulling. Saving the experiment was up to me.

I've already written about how I enjoy physical work, and I do. So when Paul told me I would have to pull it, I deliberately didn't act the least bit disturbed, and I certainly wasn't mad at him—I knew how hard he'd been working. That summer I was particularly determined to pull my own weight, because I had something to prove about women being capable in field work. I knew he had hoped to gallantly prevent me from having to pull the ragweed, because I was pregnant with my first child due at corn harvest time. This meant I was about twice as large in circumference and a good twenty pounds heavier than my usual sturdy self. Had I been any more pregnant, I couldn't have fit between the thirty-inch-wide rows of corn without knocking the plants over with my belly. If I'd been a bit heavier, I might have killed the ragweed just by sitting on it for a few minutes. Nonetheless, I hoped to prove I could do it anyway, because I was a good sturdy field worker, however big and awkward I was at the moment.

Women are still somewhat underrepresented statistically in agricultural research programs, although the numbers have increased significantly in the last fifteen years. My first funding for grad school was a university scholarship for "women in underrepresented disciplines," but by the time I finished my master's degree, half the students in my program were women. All of my advisors were completely supportive, though I did have one older professor who revealed his sexism. When he tried to reschedule the university-set finals date, I told him I couldn't come at the revised time, and he asked me if I had a date then. I didn't, but I refused to answer and reported the incident to his department chair. By the time, five years later, when I was facing a field of ragweed to pull around my seven-

months-pregnant belly, I didn't feel discriminated against in the least, but I knew I had to pull the ragweed anyway. My advisor, Russ Hahn, had seemed genuinely happy for me at my announcement of my pregnancy, against all reason except his wonderful humanity, and I didn't want to give him reason to feel otherwise. Bad enough that I would be missing harvest.

In the end, the job required two nine-hour days, with a three-hour drive to the field and home. I stayed overnight in a run-down hotel nearby, and if I'd had a phone in the room I would have called my advisor and whined for mercy or help. The only mercy was that the ragweed wasn't yet flowering. By morning, though, I steeled myself and went back to pulling. The ragweed plants were probably two feet tall each, and there were probably between fifty and a hundred in each of my forty-eight plots. They weren't yet shedding pollen, but an odor was released with each pull, something like chamomile or marigold but with less sweetness to it. By the end of that ordeal, the odor was burned into my brain. I developed a permanent distaste for chamomile tea.

Throughout the job, I kept alternating between sitting, kneeling, and standing, trying to keep the repetitive motion from hurting. I thought about field laborers in California, and in the cotton fields of the pre-Civil War Deep South, and I kept trying to remind myself that my misery was nothing compared to theirs: this job was far less than a single paycheck of repetitive, hard field labor in their lives; I would get to eat whether I finished or not; I could always stop and take a break if I wanted. Nonetheless, I felt very sorry for myself. I have never hated a weed like I hated ragweed after those two days. A 1955 article in the financial magazine Changing Times described weed control as a war to be fought with "infantry tactics" and "the wholesale slaughter by chemical warfare." I had won the war through hand-to-hand combat in the trenches, following a failed attack from the chemical arsenal. I once read about a mosquito researcher who doesn't experience the usual itch after getting stung by mosquitoes. This unusual physical trait makes him the perfect person to study mosquitoes because they don't bother him. Perhaps I, then, am the perfect person to study ragweed. I am not allergic to pollen, and though I have sympathy for people with allergies, I don't really know the misery of allergies firsthand.

I do sneeze if I get too much of any pollen. Corn isn't considered a common allergen, but a cornfield in full tassel — at pollenshedding time—is an experience that can make the toughest old farmer wear long sleeves, long pants, a hat, and bandana even on the hottest day in late July, and I'll bet a long ear of corn that his nose is dripping under that bandana. When he comes in from the field, should he venture into the house for a quick bath, he'd find corn pollen in places his wife hasn't looked at in twenty years.

Corn farmers have little reason to go in the field at full tassel. When the corn sheds pollen, it's time to fix the equipment, cut some late-summer hay, or maybe even sneak in a weekend away, because corn doesn't need any tending then. Corn researchers, on the other hand, take that moment as an opportune time to measure nutrient levels in the leaves or count weed populations. At that time of year, if you said that the corn farmers were smarter than the researchers, I don't know that many good researchers would contradict you.

Ragweed, like corn, though, has to produce a lot of pollen to get the job done. Both plants are wind-pollinated, and the vast majority of people with seasonal allergies don't have any problem with regular flowers—showy, smelly, colorful displays of floral sex organs designed to attract anything from bird to bee to butterfly to bat. All these flowers, despite the advertising show they put on, can be more restrained in pollen production because they've hired flying delivery services to do the work. Wind-pollinated plants, however, have gone for seemingly free delivery—no nectar, no postage—but the price is that they have to send bulk replicas of themselves to guarantee that some pollen grains reach their target.

This stereotype is true: being a scientist has the potential to ruin a good time. I recently took my kids to the see Bee Movie, a cartoon in which bees, inspired by a young slacker (with Jerry Seinfeld's voice), decide to sue, and then go on strike, to prevent humans from enjoying the fruits and honey of their labor. All of this nonsense I can believe—fine, it's a movie. But when all the flowers of the world ultimately revive, flowering and fruiting in response to bees deliv ering pollen, I got irritable about the artistic license. First, flowers don't need pollen to remain flowering—they need pollen to make seeds, and in fact many flowers will die back after pollination is accomplished. This is why we have to pull the old blooms off many garden plants: we're tricking them into continuing to put on their gaudy displays to attract more pollen. The second cinematic problem, though, was that each plant needs pollen from its own species. Daisy pollen won't work on roses; pollen from roses in the Rose Bowl Parade won't work on all the wildflowers in Central Park. You can't mate your dog to your cat, nor your daisies with your pansies. It was all I could do to not walk out of the theater to protect my innocent children from the movie's reproductive nonsense.

Ragweed pollen is produced in bulk because without flower-to-flower delivery by pollinators, ragweed has to rely on the dumb luck of wind to bring pollen to a maternal egg. Wind direction and speed are unknown, and the distance to other ragweed plants is unknown, so the ragweed pollen is guaranteed to miss its intended target. (Despite what it feels like to the allergic humans, our noses and lungs are not the intended target for ragweed pollen.) From the perspective of the ragweed plant, any pollen in our noses represents reproductive failure. The only good that can possibly happen would be if we sneeze it out onto another ragweed plant, and somehow I feel sure that the ragweed isn't imagining that outcome.

We, as a species, are allergic to many different plants. A few unlucky people are allergic to roses and other insect-pollinated flowers, but most are allergic to wind-pollinated plants. Allergies to wheat gluten are common, and wheat, too, sends its pollen to the wind before its kernels begin to fill with starch and gluten for our bread. Pine trees, maple trees, and oak trees are all wind-pollinated, and though we may love pine nuts, maple syrup, or even acorn flour, in the spring, our lungs may wish we would flee to an island where all the food plants were pollinated by birds and exotic insects.

I said I hadn't experienced allergies firsthand, but I do live with them. My husband's allergies can be absolutely brutal. I remember once when we were dating, in college, walking back to our dorms from the biology building together; he sneezed so uncontrollably that I was actually, irrationally, afraid he wouldn't be able to stop. We have now lived in four different cities together, and it has become obvious to us both that his allergies are not simply a direct result of wind-pollinated plants in heat. We have lived in urban areas in two big cities, Boston and Chicago, and his allergies were far worse there than they have been during our two experiences with suburban-type settings. Allergies, in our immune response, may be squarely blamed on ragweed or tree pollen or whatever a person's particular trigger is, but their intensity is clearly augmented by urban pollution. Just as smoking, but not smog, is typically blamed for lung cancer, we seem also not to wish to take on industrial sources as the reason for allergies' importance to so many of us. But why should plants always take the blame?

Pollution may not be the only reason allergies worsen in cities. Some lines of ragweed, according to weed researcher Toni Di-Tomasso, are highly tolerant of road salt, a characteristic that is rare among our native wildflowers. We know that weeds tend to spread easily by traffic along old cart roads, trails, train tracks, and paved roads, but we may be not only spreading them but actually helping the weeds grow there by salting out the desirable species, leaving more space for ragweed. Since ragweed can flower and produce pollen even at quite low plant heights, mowing roadsides, though necessary to maintain visibility, is not enough to eliminate ragweed from human passageways. Perhaps ragweed should have been my research topic after all.

Rachel Carson, in Silent Spring, notes that the whole practice of roadside weed control is part of what led to the spread and proliferation of ragweed in the first place.

Many thousands of gallons of chemicals have been discharged along roadsides in the name of ragweed control. But the unfortunate truth is that blanket spraying is resulting in more ragweed, not less. Ragweed is an annual; its seedlings require open soil to become established each year. Our best protection against this plant is therefore the maintenance of dense shrubs, ferns, and other perennial vegetation. Spraying frequently destroys this protective vegetation and creates open, barren areas which the ragweed hastens to fill. It is probable, moreover, that the pollen content of the atmosphere is not related to roadside ragweed, but to the ragweed of city lots and fallow fields.

In the seasons since grad school, I continue to remember those two days of pulling ragweed every time I see the plant. But like the memories of my labors in childbirth, this one has mellowed with age, and more of the sense of triumph remains in memory than the effort or intensity of the work. Last summer, on the edge of the pool property next door, I saw a ragweed growing in a sunny space that had been cleared of a multiflora rose. I looked at it for a moment, wondering if I should pull it or let it be. I thought of how silly it is to fight a weed that was doubtlessly thriving all over Pittsburgh at that very moment. Then I thought of all the people who have allergies, who come here all summer, and I thought of facing a whole field of ragweed like that. I reached down to the ragweed plant, still prepubescent and innocent, and pulled it up by its roots. And then, remembering those two long days and the relief of victory, I smelled its scent on my hands and smiled.

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Responses

  • penelope
    Is japanese knotweed same as ragweed?
    7 months ago

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