Ragweed: Allergen or Appetizer?

In late September we throw open the sash windows to our apartment. Soon after the welcome, dry air of early autumn flows through in a cross-draft, we sneeze. The culprit is probably ragweed, whose green spires of flowers have begun to release their fine pollen. It travels effortlessly, and can be broadcast for miles. Ours only has to waft three blocks, from nearby Prospect Park, where giant and common ragweeds thrive. The first grows in imposing colonies in high shade, and the second in full sun, its feathery leaves cropped short by lawnmowers and foot traffic, but flowering defiantly ankle height. Instead of resenting the allergen, I have learned to welcome those flowers. This is when I collect ragweed—to eat.

It has been an interesting—and continuing—adventure. Here’s a taste.

Photography by Marie Viljoen.

When I first encountered giant ragweed (Ambrosia trifida) one early summer, it was lush and tropical. I did not know what it was, so I was without prejudice, not associating these grand plants with its notorious pollen. Crushed, its leaves smelled herbally appealing. Could it be edible?

Later in the summer, as the intriguing flower spikes, formed, I became even more interested. At home—in books and on the Web—I began to explore.

In my search for clues to ragweed’s possible use as food, there was not a lot to go on. There was a single reference (in Native American Food Plants, by Daniel E. Moerman) to the roots of a different species of ragweed being valued by Native Americans as a food. There was talk of ragweed seed caches in archaeological sites. Prof. Kelly Kindscher includes a brief chapter on ragweed in his Edible Wild Plants of the Prairies, writing that “the plant was even cultivated” by prehistoric Native American nations.

My investigation progressed in a practical way, with small, exploratory nibbles.

When I began photographing giant ragweed I realized that its inconspicuous flowers are mesmerizingly beautiful. Magnified on a laptop screen their structure is organized and exquisite, alien and efficient. Minus petals or sepals, the yellow pollen in these male flowers is clasped tightly in downcast clusters, waiting to dry, when it is released by a whisper of wind. The pollen is captured by the small, nigh-invisible female flowers at the base of each male, where the seed forms; when mature it is viciously spiked at one end. These seeds have been identified at archaeological sites, and speculation abounds. Could they have been used for food, or medicine? I find it tempting to hypothesize—without any supporting evidence—that the male flower, so accessible and abundant, might have been the targeted part of the plant for food, while the seeds may be all that is left as a clue to ragweed’s possible significance in diets long-forgotten.

Ambrosia, the botanical name for the ragweed genus, may refer to the food or drink of the gods in antiquity: “This seems like a strange name for a group of non-showy plants with bitter-tasting foliage,” says Illinois Wildflowers’ website. But has anyone chewed a branch of raw rosemary? Or thyme? Bitter! And intensely aromatic. Ambrosia is derived from ἄμβροτος (ambrotos), Greek for immortal, or not-dying; so while no one knows why Linnaeus gave the mellifluous name to North America’s ragweeds, when it was first described scientifically, could it have been because he was aware that it was valued as a medicinal plant by Native American nations (which it was)?

Fast forward. After two years of edible experiments ragweed has become a regular seasonal ingredient in my kitchen. The young leaves of both species have a good, herbal flavor used sparingly, and I always blanch them for a couple of minutes in boiling water. Blanching smooths their texture and mellows their flavor. Giant ragweed tastes milder than common (A. artemisiifolia).

I use the tender spring leaf tops and early summer flower buds of giant ragweed to fill tarts and savory buns, and as toppings for focaccia and bruschetta. The flowers taste nutty and unique, and are pleasant after the blanching. Raw, they are slightly bitter, and their texture mealy. Curiously, common ragweed’s flowers are significantly more bitter, so I skip them.

The mature flowers of giant ragweed—blanched or steamed—go into savory, custardy tartlets or hand pies, and are tossed with barley or lentils in warm salads. Dried, these male flowers keep indefinitely and are deployed as a flavorful ingredient in seed crackers and breads.

For the curious, the only time the pollen becomes an issue is when these dry flowers are stripped from brittle stalks. A mask worn for five minutes during prep is the pandemic-trained answer.

While I would not go so far as to describe ragweed as ambrosial, I would call it well worth eating. And it begs the question: Does eating the pollen qualify as a form of immunotherapy?

The adventure continues.

Ragweed collection tips: Pick the tender leaves at the top of plants in spring and early summer. Collect the male flowers before they release pollen, in late summer. Avoid plants growing in industrial lots or near roads; ragweed is good at soil remediation since it can absorb heavy metals. Studies show that plants that do have the highest concentrations in their roots – think carrots! – followed by mature stems and leaves. Young, developing foliage, flowers and fruit are the least likely to be affected.

Seed Crackers With Giant Ragweed

I developed this cracker recipe for attendees of my plant walks who follow a gluten-free diet. It is very adaptable: you can use any store-bought or wild edible seeds, and seasonally changing herbs. In late summer, I add ragweed. (Psyllium is the husk of Plantago species. I make my own but it can be bought online or in the health aisle of some stores. It is essential for binding the seeds together and thickening the mixture.)

• 11.5 ounces mixed seeds (e.g. sunflower, sesame, pumpkin, hemp, flax, lamb’s quarter)
• 1 ounce (about 1 cup) dried ragweed flowers, stripped from the stalks
• 3 Tablespoons psyllium
• 1 Tablespoon fresh herbs (e.g. monarda flowers, summer savory, thyme)
• ¾ teaspoon salt
• 13 ½ fl oz (400 ml) water

Preheat the oven to 250’F.

Combine all the dry ingredients in a mixing bowl. Pour in the water and stir well. Allow to sit for 15 – 20 minutes. It will transition from thin soup to thick mush.

Prepare 2 – 3 large baking sheets: Cover each sheet with baking parchment.

Place a heap of the seed mixture on a sheet. Using the back of a wet spoon, spread it out as thinly as possible, working from the center out.  Wet the spoon periodically to help prevent sticking. Patch any tears. You want it to be about the thickness of a single sunflower seed. Fill the whole sheet – you can always add more mixture to the edges if you run out.

Slide the trays into the oven. Bake for 1 hour and then carefully turn each seed sheet over. Bake the other side for another 30 minutes to hour. Test for doneness by lifting a corner of cracker – it should be quite rigid, not flexible. If it isn’t crisp, keep baking. Remove carefully from the trays and cool on wire racks. When cool break into pieces and store in an airtight container.

For more on foraged plants, see:

• Beach Plum: A Resilient Native Shrub for Flowers, Fruit, and Gin
• Honeysuckle Cordial: A Delicious Way to Control an Invasive Vine
• Where the Wild Ramps Grow: Lessons in Sustainable and Sensible Foraging