They wouldn't be a threat, here.
But they sure would be a royal pain in the rear. These are probably sugar/fat ants.

Here is a YouTube demo:
http://www.youtube.com/watch?v=ij5js66ic7w

From an article on same:

A Word on Boric Acid

Boric acid is a white, inorganic powder chemically derived from water and boron, which is mined from vast mineral deposits in the ground and used in consumer products such as laundry additives, toothpaste and mouthwash. Deadly to cockroaches, boric acid is low in toxicity to people and pets, and is even used as an eyewash albeit in a 1% water solution. It is also odorless and contains no volatile solvents. Boric acid has been a favorite weapon against ants and roaches for more than a century, and is one of the most effective cockroach control agents ever developed, provided that it is used correctly. CAUTION: It should be kept away from children and pets.

Here is another ant bait recipe:

Mix three parts peanut butter with two parts jelly and add one tablespoon of boric acid per six ounces of mix. Place the bait on pieces of paper so stuff it into large straws and place where you see the ants foraging. Again keep out of the reach of pets and children.

A good article at the link, below.

Ants are repelled by:
Apply scents and substances that ants don't like. Vinegar, peppermint oil, cinnamon, black pepper, cayenne pepper, whole cloves, and bay leaves are all examples that have varying claims of success.[3] However, some of these might be harmful to pets and irritants to curious children.

When I had a problem with grease/sugar ants in a container, I stuck a lot of cinnamon sticks in the container. The ants left. I don't know where they went, but they sure left the container.

Jeri

Here is a link that might be useful: Boric Acid/Ants

Ant hills are great for soil drainage, and usually ants don't harm plants. However, there are hundreds of species with different habits. I wouldn't do anything unless you notice harm.

I don't know if ours are brown or more pale/reddish, but they bite me viciously even if I'm not doing anything to harm them and leave big, very itchy red spots. I truly dislike them.

Ingrid

Thanks for all the help.

Andrea

I just went through this with my dahlia patch... the ants "Farm" aphids on all the dahlia stems, leaving them covered with icky excrement, as well as the fact that aphids are a vector for the spread of dahlia viruses.(THey actually suck the liquid out of the pphids and tend them like herds of cows!) I had them on 80% of my 200 plants. IT was a nightmare! And by "on" I don't mean one aphid, but a colony reaching up a number of the stems and disfuguring the blossoms!

We got rid of the problem by multiple attacks back. First, Husband poured gas on the anthill (which was off on a strip of uncultivated land) after the ants had gone in for the night, and before they left it in the morning. He did this until there was no more sign of ants. At the same time, I removed the foliage up the first foot from the bottom and weeded out all weeds so they could not climb up into the plants from the weeds. THen I sprayed all the aphid colonies up on the dahlia bud stems with a mixture of 2 parts water to one part ammonia. I also sprayed the stems they would have to climb to get there. I did this every day for 3 days then every other day the next week and haven't had a problem since.

Husband keeps an eye out for new ant hills around the edges of the property. He has destroyed about 3 of them that the escapees have tried to rebuild. We have a lot of wild land the ants are welcome to but they can NOT make their home in my garden or use it for a food factory!

THe ammonia will discolor the flowers it is sprayed on, but it doesn't hurt the plant and in fact becomes fertilizer for it. Don't spray on a hot sunny day, but in the early morning or late at late afternoon works. WHere the infestation was the worst I broke off the tops of the stems where they were full of aphids and destroyed them. Without their food supply the ants that were left went elsewhere.

We tried numerous other methods and none worked. One piece of research said that ants to not actually eat so putting poison out for them to eat does not work. They only take liquid nourishment. We tried some of the poisons with no result at all.

I don't know what you do it you have ants without aphids.

Most ants are killed by ammonia. Windex with Ammonia D has enough ammonia in it to kill grease ants on contact. I have killed fire ant hills at work with boiling water and ammonia.

Several species of ants actually eat termite eggs. While many won't physically hurt your plants, as has been mentioned, they will farm aphids, and they also are attracted to any other "honey dew" from sucking insects. Too many in one place, too large a colony and they can reduce the soil contact to your plant roots enough to nearly kill them. They build underground colonies, loosening the soil around the roots so water flushes through too quickly and can't be absorbed by the plants. It's particularly bad when they build in pots.

I've had good success using cinnamon sticks to repel them, and I've also have very good success using Grant's Ant Stakes to get rid of them where I don't want them. Boric Acid does work quite well inside buildings, but it hasn't worked well outdoors as it dilutes in water and blows away in the wind. You can find it under several brand names. Roach Pruf is one of the most widely advertised and most expensive. PIC is the most cost effective here and comes in a squeeze bottle, making application much easier and faster. Usually it's packaged in one pound packages as insecticide. You may be able to find it elsewhere in larger sizes. Kim

Well, I am truly armed now! If I have any problems with the little critter, it will be my fault.

Thanks again to all you experts (definitely compared to me).

Andrea

We have a lot of fire ants around here. They are definitely a problem. I know of a man that died after geting bit. I have an ex sister-in-law that has to carry an epi pen because she went into anaphylactic shock from a fire ant bite. When I see a mound I stop whatever I'm doing and go get the Amdro. It kills the whole mound quite well.