We have these weeds in our yard and I'm worried that they may be hogweed? Can...
This does look a lot like Giant Hogweed (Heracleum mantegazzianum).
There are a number of plants that look like hogweed, - most of them are in the same family - and most of them are considered invasives.
Be very careful working on or around this plant. I contains a chemical that causes phyto-photodermatitis - a painful and disfiguring skin rash.
Here is a link that has some excellent information about identifying, and eradicating this beautiful, dangerous giant:
I hope this is helpful. Please contact AaE again if you have further questions.
Thank you for your response. The stem of these plants/weeds are distinctly square. Could a hogweed have a square stem? Or might that rule it out as being hogweed? Thanks again!
I was unsure if these stems were ridged - thanks for clarifying that. It is most likely Cow Parsnip - a relative - and a native plant that can also cause skin irritation.
Here is a quote from Hansen's Northwest Native plant Database:
The 'juice' from Cow Parsnip leaves and stems may sensitize the skin so that it is very easily sunburned. Washing off the juice and wearing long sleeves for a few days apparently is the ticket after exposure.The umbilliferae of Cow Parsnip (Heracleum lanatum) contain furano-coumarins which, when exposed to sunlight, cause significant photo-toxic reactions (photosensitivity). One of the more common skin reactions to Cow parsnip, is the ‘weed eaters’ or ‘strimmers’ dermatitis. When string trimmers are used to clear long grass, components of weeds are usually mulched and scattered in all directions, often coating the legs and arms of the operator. The sap of the plants then gets on the skin, and, when exposed to sunlight, gives rise to a very characteristic rash which may be severe and persist for many months.For more information, please see the Telemedicine website at www.telemedicine.org/botanica/bot5.htm
I'm curious to hear if you think this is the same plant...Thanks for your additional information.