When searching for information about carpenter ants (identification, control, and other such information), I came across this link that provides some information in this regard, and should help you to learn more about this problem. Here are some excerpts from this site:

The presence of a few foraging ants in the home, or 1 or 2 winged queens during swarming times does not mean you have an infestation. These foragers may merely be scout ants seeking food or nesting sites or queens that have flown in an open door.
Foraging ants have been seen entering homes along telephone wires or along branches touching the roof or even from ground trails that come under a door. In such cases, the house may be a nesting area.
If ants are coming in, there may be a nest outside the house and eventually they may establish satellite colonies in some part of the structure. Be certain they are carpenter ants and not moisture ants, termites or yellowjackets.

Most infestations were in houses with these characteristics:

* Wood frame
* Crawl space
* Cedar or plywood siding
* Moderately to gently sloping roof
* 5-25 years of age
* Vegetation (trees and shrubs) surrounding the house
* “Structures located near the edge of the forest were more liable to attack than those located further away.” This is because the ants which have well-established nests in trees or stumps can easily move to the nearby house and establish satellite colonies.

If you are infected with ants in your plants, then you have a serious problem. This is the link of a commercial site that will help in this regard. This site has descriptions and recommendations for control of the more common household ants such as the the: Argentiine Ants Carpenter Ants, Red Fire Ants, Ghost Ants, Odorous House Ants , Pavement Ants and Leaf Cutter Ants.
You will also find links to other entomology sites concerned with ants and a handy link to determine the difference between the termite or the ant.

Unless you can treat the nest directly, spraying is not an effective solution for small ants, unless you use a nonrepellent insecticides or “undetectable” liquid treatments such as Dominion 2L, Termidor or Phantom. Unlike older insecticides, nonrepellent insecticides can’t be smelled, tasted, or even felt by pests. So they crawl through the treated area, not knowing that by ingesting treated materials or merely contacting the insecticide, they’ll die.