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Great and woolly burdock: Also naturalized are the great burdock (Arctium lappa), and the less-weedy woolly burdock (Arctium tomentosum). The great burdock has towering flower stalks up to an amazing 9 feet. You can tell great burdock from the “common” form by the size, and by the arrangement of the flowerheads. The great burdock‘s flowerheads are arranged in flat-topped clusters at the top of the stems. The woolly burdock has fleece on the outside of its flowerheads.

Japanese gobo: Lastly, in the vegetable garden and truck farm, there is gobo, the Japanese cultivated version of great burdock.

CULTURE AND REPRODUCTION

Growing conditions: Burdocks like sun or part shade, and any type of soil, as long as it is well-drained. Burdocks have long-tap roots that hold about half the biomass of the plant, up until flowering time, making the plants seriously drought resistant.

Burdock is a biannual. Under ideal conditions, burdocks are bi-annuals, forming a basal rosette (low circle) of leaves the first year, and then dying after they flower in their second summer. A 1994 University of Manitoba study by Norm C. Kenkel and Kelly Graham, however, indicates that if conditions aren’t ideal, common burdock will remain in its immature stage for up to 5 years. The flowers, of course, are followed by the notorious seed-burs.

Burdock spreads only by seed: The seeds are definitely spread via the hooked burs hitch-hiking on passing birds, humans, and furry critters. It may also be that birds eat and spread the seed. However, while there are innumerable reports of birds roosting on burdock, eating the seeds, and using the seed fluff for nesting, there are some reports that burdocks seeds may be poisonous to some birds. Further, while burdock pops up under bird-roosting places, I haven’t found any studies that confirm that the seeds are spread via bird-gut. It is said that it took common burdock some 200 to 300 years to spread to the West Coast, a slow creep which would be more likely if the seeds had to hitch-hike, rather than fly, at least most of the way.

Picture: Common burdock flowering in part-sun, First Presbyterian parking lot, Stamford CT, summer 2004

Burdock needs infrequently distributed soil. Burdocks are normally found along roadsides, barnyards, fence lines and the like where the soil has been disturbed. The disturbed soil allows the burdock seeds to germinate and the seedlings to get a foothold. The period of disturbance has to then followed by a period of non-disturbance long enough for burdock to complete its multi-year cycle and make more seeds. Lastly, more disturbance is need for the new seeds to get going. Thus, burdock’s spread is inhibited by its need for once-in-while disturbed earth. Burdock can’t get established in undisturbed areas, in fields that are tilled every year or in areas that are mowed too frequently to allow the plant to flower.

Burdock as an isolated planting: Because of the special needs of a bi-annual that spreads only by seed, common burdock often occurs only as a isolated plant or two. When confined to isolated plantings, as it is usually is in the sub/urban environment, burdock “plays nicely with others” and is not in the same class as mugwort which crowds out almost everything in its path. In the ‘burbs, burdock is not generally as harmful to the environment as the sub/urban sprawl itself, and, in many ways, is just a part of the sprawl.

Burdock as a dominant species: Unfortunately, when conditions are ideal, common burdock also occurs in large patches. The University of Manitoba study was occasioned by common burdock becoming the “dominant understory species” in the Manitoba Delta Marsh area. I’ve been told that the area is open woods, with enough sun for burdock. (I wonder: what provided the necessary occasional disturbance of the earth? Could it have been the good ol’ white tail deer?)

Picture: Common burdock “playing nicely with others” next to a driveway along 3rd Street, Stamford CT May 2005

HAZARDS OF COMMON BURDOCK:

Burdock is considered "low risk" by the poison centers, but tell that to human parents and animal caretakers. The burs can cause serious injury if they get in the eyes or are ingested (very rare). Mostly, they're just very difficult to get out of hair and fur. (I once suffered a major haircut after crawling through a mess of them.)

Common burdock is a bird-killer!!! Now, here’s the bad part: there are several reports on the Internet of hikers finding the dead bodies of small birds such as goldfinches, kinglets, and hummingbirds that became trapped in burdock burs and then died of starvation and exposure. See an eyewitness report on the site of my colleague, Walter Muma.

When I first read about the bird-killing on Walter’s earthcaretaker.com site (thank you Walter for publishing this!), I was astounded. You can find innumerable pictures on the web of birds happily posing on burdock. I’ve known common burdock my whole life as a live-and-let-live neighbor, hair-snarling issues aside. Now, I find out it is a mobster. How? The best I can figure out is that, since all the bird-killing reports I’ve read came from hikers, the bird trapping tends to happen in the wild where burdock gets loose and grows densely enough that the burs can ensnare the little guys. If any reader has better explanation, please let me know as I can add to this article.

After this article was written, the following was received from noted ornithologist, Todd Jason Underwood, who has studied the issue:

“Regarding your question about where entanglements occur, from my observations, they seem to occur where there are large concentrations of burdock plants. I have only found one or two birds (out of about 30) entangled where there are isolated plants. Entanglements also appear more common where birds are concentrated during migration as most entanglements occur during fall migration. Another important thing to note is that burdock entanglement occurs with other animals as well. Insects are commonly caught as well as bats. I even found a dead northern leopard frog hanging by its mouth from a burr.”

Picture: close up of the deadly, bird-ensnaring burs; note the curved ends.

THE EASY WAY TO GET RID OF IT (and other bi-annually spread only by seed)

Fortunately, for us, the University of Manitoba study rejected any use of herbicides as “expensive and not environmentally friendly” (good thinking!). Having not taken the easy way out via chemical warfare, they hand dug the young ones, and cut down the bolting ones which were dying on their own anyway- no need to dig up the root. The non-flowering plant material was shredded and returned to the earth; the flowering parts were taken away to prevent adding to the seed bank. The study concludes that you could save the labor of digging and just take out the flower stalks. This latter approach would have the added advantage of not re-disturbing the earth. In any case, several years’ vigilance would be needed until the seed bank ran down.

BURDOCK USES

Human use: Burdock has been used in Eurasia since time-immemorial for medicinal purposes and as a cooked vegetable. When the European colonists imported it, the Native Americans found that the first year tap-roots and the second year stems were good eating. They also used it for medicinal purposes. One report says that they even made the burdock leaves into hats. Burdock’s high fiber content also allows it to be used in specialty paper-making.

Today, burdock continues to be widely used in herbal remedies. Modern chemical analysis confirms that burdock has anti-bacterial and anti-fungal proprieties, and also has anti-cancer properties similar to broccoli, cabbage, carrots, yams, and the like. It is also proven useful as a topical. Commercially, the burdock used seems mostly likely to be gobo. Note: Burdock is also a diuretic and has some other properties that indicate usage should be controlled, so, as with any other herbal remedy, do your homework before you try it!

In the wild, you can use burdock fiber to make cordage, and use the burs for “Velcro”. Juice from the crushed leaves is said to be a good topical remedy for poison ivy and the like.

Burdock as food: They say to cook both the first-year roots and second-year stems by boiling for about 20 minutes, then season to taste, like parsnips. Before, cooking the stems should be peeled, and roots scrubbed with a scouring pad, to remove the bitter rind. However, be cautious about harvesting burdock or any other uncultivated plant for culinary purposes: plants growing along roadsides, parking lots, and driveway may contain heavy metals from car exhausts; plants growing near dumping places or under the eaves of buildings may be polluted with all kinds of horrible chemicals.

Buy it; grow it, but take off the burs: If you want to try some, gobo is not that hard to find at North American green grocers. Alternatively, you can grow burdock in a sunny place. If you do grow it, or see it growing wild, please remove the flowers so the bird-killing burs won’t form.

Picture: Burdock flowers with a bumble bee, First Presbyterian parking lot, Stamford CT, summer 2004

Picture: Come-of-themselves burdocks looking liking great “landscaping” by the stairs leading to the Mill River walk at Scalzi Park, Stamford CT summer 2004

This issue updates and replaces issue 73, August 17, 2003,