Saturday, 31 July 2010

Giant Hogweed in Muskoka

Giant Hog Weed. Yes, it is in Muskoka. These photos are from Bala. It is creepy. A huge, silent beast wafting in the breeze, producing many seeds. The plants were brought in from China for ornamental purposes. They now fall into the invasive species category.

The plants, near Weismuller's lumber, are quite tall, the plant can grow to be 1.75 m. It's found in Port Carling,

The stems are quite large (2 - 8 cm in diameter), lending themselves to pea shooters, and much danger for small children. Immediately wash the area with soap and water and stay out of the sun.

The sun causes the reaction, and much care is required. It causes phytophotodermatitis. Within 24 hours you will get large blisters and emergency care may be required. Phytophototoxicity is amplified by humidity and perspiration. The blisters peak between 1 to 3 days.

Plant Poisoning, Phytophototoxins: eMedicine Emergency Medicine

by SM Shepherd
Phytophotodermatitis (PPD) is a phototoxic inflammatory dermal reaction induced by exposure to certain light-sensitizing plant products followed by exposure to long-wave ultraviolet light (UV-A 320-380 nm). Both components (plant and light) are required; neither agent alone can cause phytophotodermatitis. 

• Giant weed that burns and blinds spreads across Canada [National Post]
• Giant weed that can cause blindness popping up in Ontario, B.C. [Globe and Mail]

A forestry official confirmed two new findings of giant hogweed last week in Renfrew County, west of Ottawa. It has previously been spotted in Newfoundland, New Brunswick, Quebec, southwestern Ontario, Alberta and British Columbia. About 50 plants were spotted in Toronto’s Don Valley two weeks ago.

Giant hogweed is already rampant in parts of Europe including England, where the rock group Genesis wrote a 1971 ode to the plant and its “thick dark warning odour.”

Its sap is carcinogenic and teratogenic, meaning it can cause cancer and birth defects.

If you get the sap in your eye, the chemical in it, furocoumarins, can singe the cornea and cause temporary or permanent blindness.

For more information on identifying or removing giant hogweed, call the Invading Species Hotline at 1-800-563-7711, or visit or  
Thanks for the tip from Matt @ Muskoka Lakes Winery.


me said...

It is a nuisance. I remember the same warnings on TV in England some 15 or so years ago and have seen the plant growing in ditches but have never met or heard of anyone who has been affected by it. Thankfully.

Now wild parsley, that's a beast that can be in everyone's back yard, and poison ivy, how do I get rid of that when it's growing under the cedar hedge?

PLants eh, cover it all with concrete

Gill - That British Woman said...

it's in our area (Mono) as well, as per the local newspaper......I had never heard of it until I read about it.


me said...

Parsnip, I meant wild parsnip

Cloudia said...


Aloha from Waikiki

Comfort Spiral

helenmac said...

Invasive, invasion, this weed deserves all such names. Had never heard of it before. Is it native to Canada? Or where did it come from.
Thanks for all the information.

Ann said...

I take it you made a handsome profit from selling your house, and hence your pot of gold.

Where are you in relation to Windsor? I studied in Windsor U in 1975-77.

Thanks for visiting.

Ann said...

watch your video with interest. I don't know if they are here in New Zealand.

New Zealand is very strict with bio hazard. We try to keep these "foreign seeds out." The didymo came in though.

W.C.Camp said...

Wow 8 CM, that is some plant. Sorry it is so pervasive and troublesome. It looks quite majestic ... uh at least until you get it in your eye - then you can't really tell! W.C.C.

helenmac said...

I looked it up and it is all around Michigan as well. I have seen cow parsnips once in northern Wisconsin. Thanks again for a great posting!