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Issue No. 166 - May 29, 2005
by Sue Sweeney
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| I used to think that tropical-looking burdock would be
great as the star in a garden of pest and drought resistant,
edible, native and naturalized plants. Then I found out what
happens when burdock gets out of control. |
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| Picture: Common burdock, North Stamford
CT, May 2005 |
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BURDOCK FAMILY
Common burdock: Burdock is a member of the
composite (daisy) family, like its roadside
companions, chicory and dandelions. There are at
least three kinds of burdock present in North
America, all Eurasian imports. The best know is the
"common" or “lesser” burdock (Arctium minus),
which is pictured in this article. Common burdock
has flower stalks rising knee to shoulder height.
Common burdock is reported to be found in all
providences of Canada and all parts of the USA
mainland except Florida and, perhaps, some areas
near the Great Lakes. I believe that it has also
found its way into Mexico.
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. |
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| Picture: Common burdock flowering in
part-sun, First Presbyterian parking lot, Stamford CT,
summer 2004 |
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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?) |
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| Picture: Common burdock “playing nicely
with others” next to a driveway along 3rd Street, Stamford
CT May 2005 |
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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. |
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| Picture: close up of the deadly,
bird-ensnaring burs; note the curved ends. |
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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. |
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| Picture: Burdock flowers with a bumble
bee, First Presbyterian parking lot, Stamford CT, summer
2004 |
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| 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 |
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