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Poisonous Plants |
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Poison Ivy
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The Monday Garden
June 27, 2004, issue no. 118
Fun in the Sun:
Poison Ivy
by Sue Sweeney
See also Enhanced Species: Poison Ivy
(August 24, 2003, issue no. 74) |
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What would summer be without old-fashion hot dogs,
sunburns and poison ivy? All are life-threatening,
if you count the chemicals in the hot dog and the
carb’s in the bun. |
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| picture: Poison ivy flower buds,
Hoyt Street Alley Stamford CT May 2004 |
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Did you know that poison ivy is a problem only for
humans? Birds, of course, spread the seeds galore.
But did you know that the seventh most important
Indiana deer food is poison ivy? (How does the USA
Forest Service figure this stuff out?). Rabbits like
it, too. Bees make great honey from the pollen,
which fortunately isn’t toxic to humans. Goats, it
is said, like poison ivy so much that they are an
effective control. Mysteriously, the toxins don’t
pass into goat milk. And squirrels nest in it.
Do wild critters think of this human-enhanced
native species (See
Issue 74) as “human-bane”?
FAMILY HISTORY: Poison ivy (Toxicodendron
radicans) belongs to the family Anacardiaceae
(Cashews and Sumacs). The 600 family members are
mostly tropical. All are trees, shrubs or woody
vines. Many have edible seeds or fruits such as
cashews, mangos and pistachios. The family is also
known for useful tannic acids, resins, oils, and
lacquers (e.g. the Japanese lacquer tree).
Poison ivy itself (which is either one
species, along with poison oak, or about 15
– the toxicologists don’t agree), is native
to a good part of the Americas (more eastern
and northern but you can get a rash in
Mexico City and the Bahamas) and parts of
Asia. Early European visitors, astoundingly,
took the stuff home because they thought it
would look pretty in the autumn garden. It
now grows the British Isles, Europe, and
Australia. |
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picture:
Poison ivy enjoying the view at
Stamford's Cove Island
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| Picture: Poison ivy on a
stone wall, Bedford Street, Hoyt Street Alley,
Stamford CT June 2004 |
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HOW IT WORKS: All parts of the poison
ivy plant (except the pollen) contain a
pale, yellow oil called “urushiol”, after
the Japanese word for lacquer. Urushiol is
chemically stable so it doesn’t break down
or evaporate easily; it’s sticky so that it
readily adheres to anything it touches, and
it’s not water soluble so it’s hard to wash
off.
If this weren’t enough, urushiol starts
to absorb through humans epidermal skin in
minutes. It bonds with inner-skin proteins
to create new compounds, which the immune
system of 80 to 90 % of humankind treats as
an invading disease. So the rash, blisters,
etc, are all our allergic reaction to the
plant. Sort of like a thousand mosquito
bites. Like auto-immune diseases, a serious
dose of poison ivy can damage joints and
internal organs. So if you get a major
attack or it affects eyes, lungs, etc., get
yourself to the emergency room ASAP. |
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picture:
smooth-edged poison ivy leaf |
picture:
toothed poison ivy leaf
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picture:
lobed poison ivy leaf
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picture:
oak-leaf shaped poison ivy leaf
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The chemically-stable oil is always active
in the plant, dormancy and death, not
withstanding. Century-old lab specimens and
unwashed camping gear have caused rashes.
Even fire doesn’t destroy it. When poison
ivy is burned, the urushiol bonds with the
soot particles, and happily floats off in
the smoke (and into your lungs). Don’t ever
burn the stuff, and watch out for forest
fire smoke. Just like the grand jury,
past immunity is no guarantee of future
immunity. Because we’re talking an
allergic reaction, the effect is cumulative
with repeat exposures. You might get a very
mild case the first time but that just your
immune system warming up. Also, the reaction
will be less if your immune system is
suppressed. However, the reaction increases
as skin thins with age, and if your natural
protective oils are thinned by washing or
natural causes. Lastly, the oil is not on
the plant’s surface until secreted through
even the smallest bruise. So if the rabbits
were dancing around the patch right before
you got here…
Lastly, urushiol not only adheres to
anything it touches, and stay on the surface
a long time, it transfers readily from
surface to surface. Like from the dog’s coat
to your face. It doesn’t take much; urushiol
is so potent that they say that a ¼ ounce
could give the entire human race a rash.
LEARN RECOGNIZE THE PLANT So what
to do? Any boy scout (and all girl scouts)
can tell you to learn recognize the plant
and avoid it. Look for the three leaves and
the almost-always present sheen to the
leaves. Learn to tell its various leaf forms
and colors; If you’re not sure, treat the
plant as poison ivy. |
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| reddish new poison ivy leaf |
light
yellow-green poison ivy leaf
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dark green
poison ivy leaf |
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pictures: winter and
spring views, Stamford CT , 2004 |
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Picture: Poison ivy
with seedlings, Hoyt Street Alley, Stamford
CT June 2004; the heart-shaped babies are
porcelainberry |
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Eradicate it when possible. You may
be able to double-wash your tools, clothes,
and the dog, but believe me it’s easier to
pull up the poison ivy than to wash the cat.
If you can’t borrow a goat, see
Issue 74 on how to get it out of your
yard; and
Issue '112
on the (sparing) use of herbicides.
Know the first aid. Since urushiol
starts absorbing in minutes, get it off
fast. It’s not water soluble so using plain
water or water with an oil-based soap (e.g
must organic products) spreads it like oil
on a fire. Use alkali soap like yellow
laundry soap or naptha. And take a shower--
not a bath -- or you could end up with a
whole-body rash. Alcohol and other solvents
will remove the urushiol (rinse with water)
but also strip the skin’s protective oils so
be even more careful about additional
contact. |
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Picture: jewelweed,
Bedford Street, Stamford CT June 2004 |
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In the wild, use any available water. To get
the oil off, use mud, baking soda, wood
ashes or bouncing bet (Saponaria
officinales) (a useful European settler,
high in saponin, makes an oil-free soap).
Whether you can find water, apply
jewelweed (Impatiens spp.) juice
(suspected to have urushiol-blocking
compounds and is a known anti-inflammatory);
a plantain (Plantago) leaf
poultice is also said to help for similar
reasons. There are over-the-counter
products, some developed for the USA Forest
Service, said to block the oil from entering
the skin and/or to remove it after contact. |
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picture: poison ivy
mixed with woodbine, a native vine with FIVE
LEAVES |
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