Apply granular diazonide...it works fast, too.
Hi Delsy, I would set out some combat ant killing bait strips when you know there is not going to be any rain. It works great for ants and believe me I had a big problem. It kills off the colony. Here is a link to check them out. They also have them at walmart.com
I use sweetened cornbread and muffin mix. It is cheap and they take it back to the mound and every ant eats it, they can't digest it and they die. If you know where the mound is, sprinkle it heavily on the mound and keep applying it as long as you still see activity. Small mounds usually take one application, larger mounds and larger ants take a few because of their size and the large mounds have a very huge population to feed.. I usually don't mind a few ants in the garden, they do eat little critters from the plants, just not mounds.
Throw your lemon or orange peels in your flower beds. No harmful pesticides and good for the soil.