https://plants.usda.gov/core/profile?symbol=hema17

If Hollywood wanted to make a movie about a horrifying plant
invasion, giant hogweeds would make a great candidate for the
lead role - they are absolutely massive, incredibly toxic, and
readily spread wherever their seeds take root.

Listed as a noxious weed in at least eight states, last week the
giant hogweed (Heracleum mantegazzianum) was spotted in Virginia
for the first time.

According to reports from the Massey Herbarium at Virginia Tech
university, about 30 of these towering plants have been found in
Clarke County, and locals are warned to keep an eye out for
sightings.

VT Massey Herbarium
@MasseyHerbarium
Today I helped ID VA’s first giant hogweed population! Its sap
causes severe burns. One plant was found in Clarke County.
Report sightings to your extension agent! ID help:
https://on.ny.gov/2JHzLKy Thanks to @herbariumkeeper and
@VTAgWeeds for ID help and report!

12:03 PM - Jun 12, 2018
23
56 people are talking about this
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Native to the Caucasus region, the statuesque plant looks like a
huge mutant version of the benign common hogweed - but it can
cause severe skin burns if you so much as brush against the
bristles on its stalks.

Those bristles, along with the rest of the plant, emit a nasty
sap that chemically irritates the skin causing phototoxicity -
severe damage to the skin through exposure to sunlight and UV
rays.

As a result, one can get huge, oozing blisters that can leave
behind scars and photosensitivity for many years (you can see
some NSFW photos of giant hogweed-caused blisters here.)

But unless you're familiar with its nasty secret, you might
think the giant hogweed looks cool - these large plants can grow
more than 4 metres (14 feet) tall, spreading their huge leaves
and producing massive umbrella-shaped clusters of white flowers.

After Britain first made the mistake in the 19th century, as an
"ornamental" garden plant it was also introduced to North
America just a few decades later, and since then it's been a
battle to stop the flowering monster's march across the
continent.

Once you have an infestation, it takes a lot of work to control
the giant hogweed to prevent its spread, as its seeds - each
plant can shed thousands - remain viable in the soil for several
years.

"In some cases, a giant hogweed infestation is best controlled
using several different methods in combination or in succession -
in other words, a two, three, or even four-pronged attack
plan," explains the New York Department of Environmental
Conservation (NYDEC).

Those methods involve cutting the plant roots, removing seed
heads, mowing them down when they're still small, and even
dosing the whole thing with herbicide. Of course, going anywhere
near a giant hogweed requires protective gear.

Weirdly enough, H. mantegazzianum isn't even the only horror
weed that's come to plague the world from its Caucasus origins.

The closely related H. sosnowskyi species, discovered in Georgia
in the 1930s, was brought into the Soviet Union for growing as
cattle feed. These days, it is by far the scariest plant you
could find in the Baltic States and Poland, where it's
considered highly invasive.

It's easy to imagine that one day far in the future, when humans
are all dead, whole swathes of our planet could be overgrown
with this incredibly toxic, fast-growing plant. Movie writers,
you're welcome.

To learn about the identification of giant hogweed and compare
it to common look-alikes, check out the NYDEC site here.

https://www.sciencealert.com/invasiv...hogweed-burns-
skin-blindness-virginia-clarke-county

"Bradley K. Shurman" wrote in message
...

https://plants.usda.gov/core/profile?symbol=hema17

The closely related H. sosnowskyi species, discovered in Georgia in the
1930s, was brought into the Soviet Union for growing as cattle feed. These
days, it is by far the scariest plant you could find in the Baltic States
and Poland, where it's considered highly invasive.

It's all a Capitalist plot ;-)