Menu

Hazard Alert: Giant Hogweed spreading in Ontario

Mature Giant Hogweed Photo Courtesy of: Jean-Pol Grandmont

Giant hogweed, (Heracleum mantegazzianum), is an invasive new weed that is colonizing in some parts of Ontario, eastern Provinces and Western Canada. Locally, it has been found in Ottawa, Halton region, Waterloo, Markham and the Don River valley in Toronto according to a report in The Globe and Mail. Giant hogweed is very dangerous. Its sap contains furanocoumarins and is toxic on contact, causing inflammation. Worse, the sap is phototoxic, which means it gets stronger when exposed to sunlight. When this happens the sap can cause severe and disfiguring blistering.  If it gets in your eyes, it can cause temporary and even  permanent blindness. It is important to note that giant hogweed is currently only being found in wild and overgrown areas like ravines, roadsides, riverbanks, vacant lots and would likely only pose a problem for homeowners with an unmowed lawn.

Giant hogweed lives up to its name, a mature plant growing to over fifteen feet in height. You can identify it by the large, serrated elephant-ear shaped leaves and a hairy, purplish-red stem.  It is difficult to identify in it’s infancy and can be confused with several other weeds- do your homework. It also produces clusters of white flowers in an umbrella-like formation in June and July.  It reproduces by seed each year.

If you find a giant hogweed, leave it alone, and contact a licenced professional weed exterminator like LawnSavers to remove it. Teach children what it looks like by keeping them informed, to keep away from the plant if they see it, and to tell you or another adult.  If you get the sap on your body, immediately wash the area with soap and water and seek medical attention. Keep the exposed area out of the sun for several days.

If you have to remove the plant yourself, make sure you are completely covered in protective clothing, and wear impermeable gloves and eye wear. Put any seed heads in a separate and tied plastic bag and dispose of it in the garbage, not the green bin, so the seeds do not spread. Roots can be deep and should be cut 12 inches deep. If you are just finding juvenile shoots, mowing regularly will kill the shoots and eventually exhaust the supply of seeds in the soil. Just be extra careful and follow the noted safety procedures when disposing of the clippings.  Since it is considered a noxious weed in most municipalities, a licensed weed exterminator like LawnSavers can use a chemical pesticide to kill the plant properly when it is young, down to it’s roots. You can also contact your local or regional conservation authority for additional information.

Please be prudent & careful.  This plant is beginning to spread far too qucikly for our liking.  It’s time for the government to step up and take responsibility and create an action plan to eradicate this imported and invasive species rather than pandering to anti-pesticide sentiment among some well meaning but misinformed activists.

For more information and pictures see: Ontario Weeds

Call LawnSavers Plant Heath Care at 1-888-503-LAWN(5296) or email us through our contact page
For general questions call TeleHealth Ontario at 1-866-797-0000 or TTY 1-866-797-0007

Get a FREE estimate! Get a FREE estimate!
    • This field is for validation purposes and should be left unchanged.
  • Coping with Covid Update: (updated 04/16/21)

    Hi Everyone, 

    LawnSavers managed to persevere through this last pandemic year with the loyal partnership of our clients.

    We are able to service lawns and perform pest control services in all our service areas,  officially on the Provincial list of essential services due to our ability to provide service safely and with no personal contact!

    Our office remains open in addition to some remote staff.   Please note our office may be experiencing a higher volume of calls.  We know how much everyone hates being left on hold, so please leave us a message or email us at greatservice@lawnsavers.com and we will get back to you in less than 24 hours.  (you can now also text us at 905-707-9994)
    Please be patient with us, we will get back to you as fast as possible.
    You can also sign up for services on our website by clicking here.

    2020 is now behind us.  Together with our customers, we face Covid-19 head-on as a community-minded local small family business and are extremely grateful to be able to survive and keep all of our loyal employees working hard with us through it all.

    2020 threw everything bad that it could at us:

    • Nine days of snow, ice and wintry weather in May.
    • One of the hottest driest summers on record with long spells of grass-killing heat and drought. Read more here in our 2020 summary blog.
    • A bumper crop of crabgrass that germinated in the perfect (rainless) storm.
    • Chinch Bug numbers were record breaking and persisted through the dry heat they love, secretly killing lawns while dormant! We can help with Chinch bug damage
    • We put together an easy to read lawn care service timeline that you can use to know when to expect us for each scheduled service in your package. 

    I want to reassure you that in every decision we make around COVID-19, our number one priority remains the health and safety of our employees and customers.  Safety, Integrity and honesty are our most important core values.  We will continue to follow strict safety guidelines that ensure “zero touch”.  We will not let our guard down on exercising our safety protocols!

    Thank you all for your understanding and extra patience during these challenging times. Our team works hard, so if you are met with our exceptional service from our technicians or office team members- please give them a thumbs up to make them smile or let me know through a quick email to feedback@lawnsavers.com

    We thank you for supporting our local, family-owned business of 31 years.
    We
     genuinely appreciate each and every one of you and promise that we will do our part to ensure our mutual safety and look forward to be back on your lawn as soon as possible this Spring

    Thank you in advance,
    Kyle Tobin
    Chief Environmental Officer