Grit Blogs > Blooms and Spoons

Canada Thistle

Canada thistle in winter 

What are your worst plant enemies? 

I have a severe problem with quackgrass (aka couchgrass, Elymus repens), which I have struggled with for over a decade. I don’t use any chemicals in my garden, so it means a great deal of elbow grease is necessary. While I have made significant inroads, I cannot ever let my guard down!  

One plant enemy I am so glad I don’t have in my garden is Canada thistle (Cirsium arvense). Are thistles a problem where you live? 

INTERESTING FACTS ABOUT CANADA THISTLE: 

  • Canada thistle is not a native of Canada. It actually has its origins in Mediterranean Europe. 
  • Another common name for Canada thistle is creeping thistleas in, it creeps you out with its insane root system.  
  • Each plant can produce up to 5,000 seeds. 
  • Each seed can remain viable in the soil for up to 20 years. 
  • Just 8 to 10 days after flowers emerge, plants can already produce viable seed. 
  • Canada thistle reproduces by seed AND by vegetative cloning a double whammy. 
  • New plants can form from the tiniest of root segments – just 1/8 – 1/4″ thick and 3/8″ long. This is why pulling and digging don’t work very well. 
  • The tap root of each plant can reach 20 feet underground in a single growing season. Isnt that incredible? 

(For more information about Canada thistle, check out http://www.agriculture.gov.sk.ca/canada_thistle_control)