I was travelling a country road and taking some photos in Halton Hills, the area I live in, when I came across this sign. Of course this peeked my interest to look closer!
I do remember news broadcasts that these were invading Ontario at an alraming rate. To be truthful, I didn't pay a lot of attention. Heracleum mantegazzianum or Asian Poisonous Giant Hogweed, is an invading species. Giant hogweed was first reported in Canada in 1949 and in recent years spread to Southern Ontario.
The concern is it's a very poisonous plant. If you get the sap from this plant on your skin it can cause severe blistering and ad burns. Sap in the eyes can temporarily blind you or it can be permanent! The burns can cause permanent scarring and any areas affected will be super sensitive to sunlight for years to come. It can take up to 48 hours after exposure for the symptoms to appear.
This photo I took below are of dead weeds, but they are still many seeds on them. I couldn't get over the height. These were about 10 feet tall! The plant can grow up to six metres tall, with leaves as big as 1.5 metres across. It is identified by large purple blotches or striping on its stem.
Below a few of the plants I saw these red markers from the University I think. Not sure if they are marking the seed fall area or new small plant growth.
It spreads primarily by seeds. Seeds can be carried by vehicles, by people, by winds … it could be a bird. Every plant will produce approimately 500,000 seeds, so the spread potential is huge. This is one of the seed heads I found. You can still see many seeds still attached.
This is a photo below is of what the plant looks like in bloom. I have seen this before and not realized what it was. I thought it was a huge plant and pretty awesome looking and they are quite attractive to look at. I am glad that I didn't stop and take a closer look as I usually would!
Interesting find! Thought I would share it with you.