Thank you, Peter!
I permit myself to copy your very generous comment below:
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Fantastic photo Enok!
I recently found out some rather ominous things about Rhododendrons
however...
- Peter Ciccariello
http://invisiblenotes.blogspot.com/
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Behold the lovely
rhododendron -- and beware its maddening toxins
Ron Sullivan
Wednesday, February 9, 2005
In 401 B.C., Xenophon of Athens, one of Socrates' students, marched off to
back the wrong contender in a Persian civil war, and had to lead a retreat
through hostile territory. He wrote a best-seller about it, the "Anabasis."
(You can find the translation, quoted below, by H. G. Dakyns online,
courtesy of Project Gutenberg, at
www.fordham.edu/halsall/ancient/xenophon-anabasis.html#Project%20Gutenberg.)
One prominent adventure was not a battle, but the commandeering of a village
from which their opponents had fled.
"Here, generally speaking, there was nothing to excite their wonderment, but
the numbers of bee-hives were indeed astonishing, and so were certain
properties of the honey. The effect upon the soldiers who tasted the combs
was, that they all went for the nonce quite off their heads, and suffered
from vomiting and diarrhoea, with a total inability to stand steady on their
legs. A small dose produced a condition not unlike violent drunkenness, a
large one an attack very like a fit of madness, and some dropped down,
apparently at death's door. So they lay, hundreds of them, as if there had
been a great defeat, a prey to the cruellest despondency. But the next day,
none had died; and almost at the same hour of the day at which they had
eaten they recovered their senses, and on the third or fourth day got on
their legs again like convalescents after a severe course of medical
treatment."
Centuries later, in the same region, the army of Pompey the Great of Rome
was ambushed by the forces of Mithridates VI of Pontus, to worse effect.
After helping themselves to honeycombs left along their route, a troop of
Pompey's soldiers succumbed to similar symptoms and were massacred while
helplessly intoxicated. Pompey went on to win that conflict eventually,
nevertheless.
Mithridates himself had a reputation as a ruthless killer and poisoner, but
his claim to fame lay in his method of immunizing himself against poison:
gradually increasing doses of every poison known at the time. (One has to
wonder about this, as some poisons are cumulative.) The poison in the
honeycombs that laid Pompey and Xenophon's soldiers low is known today, one
of the all-natural products of what A.E. Housman, in his poem on the
subject, calls "the many-venomed earth."
It's known as "mad honey": "deli balin Turkey, "miel fouin Western Europe.
Tiny doses of it in milk or spirits are taken in the region around the Black
Sea as a tonic, something to make one reflect on the elasticity of that
term. And the reason it's toxic in larger amounts is its raw material. Bees
make it from the nectar of Rhododendron ponticum, the large
pale-purple-flowered species native there.
More recent cases of mad honey disease are known from the region and as far
east as Nepal, and from Europe, where a rash of them was traced to souvenir
honey from Turkey. It's still unusual because it's rare that bees get only
rhodie flowers to make honey from, so the poison is diluted enough to make
it harmless. Other rhodie and related species are known to contain the
active ingredient, grayanotoxin, formerly called andromedotoxin or
rhodotoxin. Our local native azalea and rhodie species, R. occidentale and
R. macrophyllum, contain it and so does Kalmia latifolia, the mountain
laurel of the Appalachians.
You can still get a dose if you're dumb and determined enough to eat any
part of a rhododendron. I guess some merry soul might misguidedly festoon a
salad with the flowers, but the leaves are decidedly leathery and
unpalatable. The pollen and sap (used as arrow poison once upon a time)
contain the toxin, too -- don't sip and don't sniff! And while I'm scolding:
Don't use the twigs to roast marshmallows, and don't make rhododendron tea,
either.
Most honey-intoxication cases, absent hostile armies, resolve themselves,
but a few have resulted in death from cardiac effects and drastically
lowered blood pressure. Aside from that, the gastric effects, convulsions
and paralysis don't strike me as a pleasant way to get high, and the
hallucinations some have experienced are described as uniformly unpleasant.
One group that's probably already familiar with rhodie poisoning is
livestock handlers, including veterinarians. A sheep, goat or cow that is
hungry enough to eat those tough leaves will stagger, drool, have serious
gastrointestinal troubles and, like us, may have cardiac problems and
convulsions. It's hard to guess whether a cow is seeing visions or garbling
her speech, unless it's Clo making a bad pun. Still, it can't be pleasant,
and it can be fatal.
R. ponticum's troublemaking doesn't end in the stock pen. It was a popular
import to the British Isles in Victorian times, planted for screening and
big effects on estates, and as cover for game birds. Now it's thrived
enough, and spread far and fast enough, to imperil the ecosystems it was
supposed to "improve."
It propagates via large amounts of tiny scattered seeds and runners from its
lateral branches. It spreads those branches to shade out any understory
plants and creates an effective monoculture, and, remember those toxins?
They work against grazers, so restorationists can't use those to clear the
thickets; and they work against smaller animals and, evidently, insects, so
the rogue rhodies don't get eaten by anything. They're about as biologically
useful as plastic flamingos.
There are reports of British honeybees seemingly suffering from neurotoxic
effects; evidently, unlike bees in the plant's home range, they haven't
adapted to its toxins. There's an interesting chemical warfare "arms race"
that happens as plants and animals co-evolve, and while Turkey's bees have
figured out a way to turn grayanotoxin to their advantage in making their
honey less susceptible to raids by larger animals, other insects remain
vulnerable to it themselves.
Restorationists also report that the mulch of fallen leaves under a rhodie
thicket remains toxic enough that the humus has to be peeled up and removed
before new plantings can take hold. The plant, in smothering out several
layers of understory and preventing new tree seedlings from growing, has
even been part of why the dormouse, of all things, is endangered. Alas,
Alice, it's no tea party these days in the British woods.
*Ron Sullivan is associate editor at Terrain (
www.ecologycenter.org/terrain/terrain.html),
where she writes "A Sense of
Humus," and garden editor of Faultline Magazine (www.faultline.org).
She's a
former pro gardener and arborist.*
http://sfgate.com/cgi-bin/article.cgi?f=/c/a/2005/02/09/HOGDOB70PU1.DTL