How can I get rid of ant hills? Everything I've tried just seems to move them to another area and they're multi[plying!!
Hennepin County Minnesota
Thanks for your question.
While generally beneficial insects, ants and their hills can sometimes be a nuisance. It's important to recognize that the only way all the ants in a colony can be removed is to kill the queen. This can be very difficult to do as she is typically deep inside the hill. All of the ants that you see above ground are daughters of this queen. Their life spans can be as short as a couple of months or can extend for a year or so. The queen ant can lay thousands of eggs daily. All of this means is that unless the queen ant is destroyed, it will be very difficult to eliminate the ant hill. Even if you dig it up, it may be unlikely that you will remove the queen ant.
A non-chemical approach to dealing with existing ant hills is to spread diatomaceous earth around the hill. This often causes the ants to leave the hill but perhaps as you are discovering, they may simply establish a colony elsewhere. The reality of your situation is that outdoor anthills are often very difficult to eliminate without resorting to some type of chemical treatment.
The University has an excellent publication about control of ants:
Unfortunately all the chemicals mentioned in the above article are toxic to beneficial pollinators that add diversity to your gardens.
Sometimes I have used ant traps made by Terro. These were placed around the actual hills. If the size of your hill is over than a foot in diameter, this may not be a practical approach. Unfortunately, Terro has also been reported to harm various types of pollinators.
This site will give you suggestions for getting rid of ants outside without resorting to harmful chemicals (look at the section where natural substitutes are suggested):