Thistle can spread quickly and will compete with other plants for water and nutrients. To get rid of thistle, simply pull it out of the soil by hand. Mulch can help prevent thistle from coming back.
The purple flower heads may look pretty, but don't let that fool you. Milk thistle (Silybum marianum) can be a pain if it's growing in your yard. It's non-native and can be an invasive plant, as Keri ...