Canada thistle, also referred to as Canadian thistle, creeping thistle or field thistle, originated in Europe and was brought over to North America in the 1600s. It has now become an invasive species, with its aggressive growing and ability to spread at a rapid rate. It often outcompetes other plants for new areas to grow.
To fully eliminate Canada thistle, you must injure and deplete its root system. This is likely a process that will take repeated steps over multiple seasons. Unlike other plants, eliminating thistle is not done in one day.
One of the best ways to get rid of thistle is by using herbicides. Glyphosate 4 or 2 4-D Amine are ideal herbicides for fighting thistle plants, as they are systematic and will kill the plant down to the root.
If you are looking for an all-natural way to get rid of Canada thistle, salt and vinegar is a great choice. Vinegar is a natural weed repellent and one of the most efficient ways to get rid of thistle. It is also much more environmentally and family-friendly than herbicides.
Though mowing may not fully eliminate thistle plants, it can help prevent it from growing and spreading. It is best to mow thistle while it is in the early bloom state. Since the thistle is low on stored energy in spring, the roots will suffer greater damage.
Canada thistle can be difficult to get rid of, however, with the right process, you can successfully eliminate it from your yard and garden. Since it is an invasive species, not native to North America, it is always best to get rid of it when possible.