Knowledgebase
Invasive plant? #753427
Asked June 01, 2021, 10:49 PM EDT
Can you help me identify this weed. Is it just a simple thistle or something more nefarious giant hogweed. It has quickly taken over an area on my property and has grown to 4-5 feet tall in a week or more. Also what would be the best way to eradicate it? It is intermixed with a good amount of maple tree saplings I was hoping to promote and not hurt.
Dauphin County Pennsylvania
Expert Response
The good news is that it is not giant hogweed. It is likely Canada thistle or bull thistle. Bull thistle has a tap root while Canada thistle grows via rhizomes and can be more difficult to control. It appears that flowerheads are developing and will produce flowers and seeds from June-August. You might want to pull a few to confirm the type of root (stem vs rhizome). You want to control before seed heads develop. If the area is not too large and it is bull thistle you might want to control by pulling now. If it is Canada thistle it might require chemical control. I've attached the following links that contain additional information.
https://www.nps.gov/articles/000/canada-and-bull-thistles-acadia.htm
https://extension.psu.edu/bull-thistle-identification-and-management
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On Jun 3, 2021, at 2:52 PM, Ask Extension <<personal data hidden>> wrote:
