What is the best way to get rid of ants in your flower garden?

Apply food grade diatomaceous earth

I agree, use DE! I buy mine from Amazon. Put it in a shaker container, keep it handy and when walking outside sprinkle away. You need to replace if it gets wet. I've been using DE for years and buy food grade. That way I can use it outside in the garden and even brush my teeth with it. Sounds goofy, but it works for lots of jobs.

Pour hot boiling water on their nest.

Corn meal.

Mix baking soda with sweet n low sprinkle it around. It messes with their brain and they can't find their trails and get lost and starve. it does work I use it myself.

packaged cornbread mix that says it is sweetened and put it where they are coming in if you can find it, or even on your counter in a small lid. They will take it to the mound, everyone will eat it and die, they can't digest the cornmeal, but will take it because it is sweetened. Little goes a long way.