What’s remarkable about Hypericum perforatum
is that, outside of Europe, until very recently,
government funds were more likely to be spent
figuring out how to eradicate the herb from farmland
than how to use it for medicine. In California, they
imported a bug from Australia to eat it.
Common St Johnswort is a
European-Mediterranean native that has been
used medicinally at least since the Greeks
started to keep written records. In the
European Middle Ages, it was thought to
protect against demons (a handy thing,
today, if it’ll work for computers).
At some point, the herb got named for St.
John the Baptist but no one, today, is sure
why. In any case, the Europeans took Common
St. Johnswort with them as they spread
throughout the world, and it joyfully
naturalized across the four remaining
continents, mingling with its 60 or so local
cousins.
Common St. Johnswort is a short, shrubby
perennial that’s only too hardy and
fast-spreading. It enthusiastically
reproduces from seed and underground
runners. It thrives in hot, dry, sunny
places such as over-grazed fields. It’s
particularly widespread in Western USA and
Australia which have the extensive grazing
land and the hot, dry summers that St.
Johnswort adores. |
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You can tell most of the St. Johnswort
family by the signature 5-petal; 5-sepal
star-like flowers, with prominent center
“tassels” (stamens). Locally, at the
“kissing cousin” level, we have the several
native St Johnsworts, mostly rare plants.
There’s also an “ornamental” St. Johnswort
garden hybrid. Shown in the pictures in this
article, it’s more compact, and has more and
larger flowers than the noxious
weed/valuable herb variety. In North
American gardens (Zone 5 or 6 to Zone 7 or
9, depending on the source), you might also
see Aaronsbeard (Hypericum calycinum),
a low, shrubby groundcover from Asia with
typical St. Johnswort flower but they’re
much larger. There are other North American
cousins including a pink-flowered swamp
plant. You can tell Common St. Johnswort
by the presence of dark dots that hold the
red fluorescent pigment, hypericin. Hold a
leaf up to the light and you’ll see
translucent dots. Look for tiny black dots
on the edge of the top side of the petals.
There are also pairs of dots on the flattish
stems. Crush the flowers and you’ll get
blood-red hypericin juice, which will stain
your fingers blue-violet.
The problem with Common St. Johnswort is
that hypericin causes light-colored skin to
become hypersensitive to sunlight. Most
sources say that it primarily affects
white-haired non-human mammals, primarily
sheep, then cattle and horses, and, to a
lesser extent, goats and pigs. Some sources
do post a caution for humans and say that
sensitivity is cumulative. The affected
mammals don’t readily graze the herb but, if
they’re hungry (e.g. forging on dry,
over-grazed land) or it gets mixed in hay,
consuming as much as 1% of body weight can
be horrible for the animal. The animal can
go blind, loose large patches of skin, and
even starve to death. So you can see how
Common St. Johnswort got on the noxious weed
and invasive plant lists.
Many other members of the St. Johnswort
family produce hypericin but apparently to a
lesser degree. According to Purdue, the
toxicity of the cousins has not yet been
investigated, so handle all St. Johnsworts
with care.
On the good side, it’s fairly well
established that hypericin (or some other
chemical in the plant - it has several
active compounds) affects brain levels of
dopamine and serotonin. Hence comes the
feel-good affect. Hypericin (or whatever)
also has antibacterial and antiviral
properties, and is currently being
investigated for treating everything from
tuberculosis to HIV and herpes simplex. It’s
my own experience that the oil mixed with
arnica ointment is great for joint
inflammation. (Even Stamford‘s Dr. Nicola
Bott recommends it in the appropriate case.)
On the even-better side, since you can
barely kill it, even with Australian bugs,
it’s a very cheap, very available
broad-spectrum medicine. Indeed, some
sources say that it’s safe and easy to make
your own oil from fresh flowers – check the
web for recipes. Forget the AARP, think what
this can mean to countries where the
simplest drugs are beyond reach. (Do,
though, use caution whenever self-medicating
with herbs — “natural” doesn’t mean
harmless! And, with Common St. Johnswort, do
watch out for the possibility of
hypersensitivity to sunlight and don’t grow
it where it could endanger livestock.)
Last word: for the anti-chemical
crusaders (like me): the more nitrogen you
put on the growing herb, the less potent it
becomes. So there! |
