Taking Down Invaders: Removing Ants from Your Home and Garden

“I had problems with ants last year.  They stripped the kernals right off of my corn last year & I had ants crawling all over the stalk. I have a lot of ants all over her yard and garden again this year. I know Diazinon is gone so any ideas what I can use? ~K.”


Garden ants are part of the Hymenoptera family of insects, sharing this order with bees, wasps and sawflies. One of the first things you may recall from your high school biology is that, for the most part, these are the so-called “social” insects. They live in colonies. The mouths are built for chewing; and, each of the members of the family chew something – be it mud, leaves, wax or, in the ant’s case – cellulose. The family relies on nectar, honeydew and pollen for much of their food although sometimes the larvae and adults can be carnivorous. Most of the family members are involved in pollination in some way with the exception of our garden ants.

Garden ants have one of the most complex social lives of any animal or insect. There are three castes in each colony – females, workers and males. Before we go any further, I want you to note that the workers are neither male nor female – so there will be no talk of males not doing any work around the ant nest. In fact, males mate with winged females, then they die just before the wives get around to forming new colonies. Not a role to be relished.

Each of these founding queen females produces a new group of workers which mature quite quickly to begin their job of feeding the queen and tending the queen’s newly laid eggs and larvae.

Garden ants are spread throughout North America with colours ranging from black through brown to reddish. Ranging in size from 1/6 to 1/4 inch long, they come in both winged and wingless forms. In general, queens lay their eggs continuously throughout the warmer seasons and the colonies hibernate in winter.

Normally they spend winter below ground in the ant-nest, hill or colony but there are a few species that apparently spend the winter in garden trash. Garden ants love to eat organic matter, although a few are carnivorous, eating anything they can drag down. Many species feed on the honeydew secreted by aphids and may thus become a bit of a nuisance by herding and caring for aphid populations.

All this begs the question, “What can we do about about garden ants?” In short, the return answer has to be, “Why do anything about them?”

Some gardeners see this insect and assume it is a “bad” thing. They are scavengers. If you find them inside your tree, they is not bringing disease to the tree. Neither are they eating or wrecking the tree. What they are doing is harvesting the rotten wood, fungus and other organisms that ARE eating the tree. It is performing a caretaker function for you. Never try to eliminate garden ants from the inside of trees, they are sending a signal that the tree is in danger and ill health.

Some gardeners see a hill in their lawn and react with panic. Again, they are not creating a problem in healthy grass. Set the lawnmower to a higher setting so the grass will grow above the hill and you’ll never see the problem. Both you and the colony will appreciate this benign neglect.

Some gardeners see them scurrying around on the paving stones on patios or driveways. This is a pain in the garden as they can undermine the stone foundations. Slowly pour boiling water down the hills. If poured very slowly, the hill will likely die. It may have to be repeated several times but eventually the nest will die.

This resistance to being killed is quite noticeable in all methods you might try to eliminate the garden ants in your garden. Colonies or nests do not die quickly or overnight. Even the most effective of controls takes several days to work its way through the colony to the queen. It is the queen you want to kill as once she dies, the colony will wither away.

If garden ants are in your flower beds, then there are ways to discourage them as well as kill them. Control the aphids. Without aphids, some species will not have enough food.

Garden ants do not like wet ground. Keep the garden well watered and your problems will decrease.

Garden ants love rotting organic matter – make sure the only left-over organic matter is in the compost pile.

Ants love sugar. Put a mixture of 50:50 sugar and borax in covered bait stations and the ants will take the sugar/borax back to the nest to poison the queen. Do not spill it around the garden as borax (boron) will kill your garden plants if applied in sufficient quantities.

Make tea – pennyroyal, spearmint, southernwood and tansy are all repellents when brewed and sprayed.

Diatomaceous earth is another killer – combine this with pyrethrum and you have a potent poison that is environmentally benign.

Entomopathogenic nematodes can control ants, but you’d probably want to use a combination of Steinernema sp and Heterohabditis sp to accomplish this task.

There are other solutions being investigated – enzymes are under study – but for now these are the most common ways to take care of them.



© Mertie Mae Botanics LLC and Horticulture Talk!, 2010. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Mertie Mae Botanics LLC and Horticulture Talk! with appropriate and specific direction to the original content.


2 thoughts on “Taking Down Invaders: Removing Ants from Your Home and Garden

  1. Pingback: Knock ‘em Dead: Tried and True Way to Get Rid of Ants | Horticulture Talk!

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