The weed killer recipe will kill any plant. If the thissels are in your planted areas i.e. grass or flower bed, you would have to be real careful to kill the thistles. The best way is to dig them up. You can now get a special weed digging tool that helps to uproot them.
Honey bees love the pollen of thistle
Here's a comprehensive article that should help you. Wishing you the best.
Are thistles those white things that stick you when you walk in the grass