Unless you have some expensive plants near your foundation you can try this. BEWARE: The EPA in most states will not like this and if you get caught, you may be fined. I too have an older home with a stone foundation that also had termites. If you change your own motor oil you can use the old oil as a good deterrent. Subterranian termites can travel as deep as 6 feet or even more underground. Clear an area at least 4 inches from the base of the foundation along the outside of your house. This decreases the chance of killing any grass nearby. Take the used oil and pour it along the foundation where the foundation meets the ground. Termites must have water to survive even if they are feeding on the wood of your home. The oil not only will kill them if they try to travel through it but will also soak eventually through their tunnels they travel in preventing access to either food or water. Commercial termite treatments are water soluble thus will wash away after a couple years. Oil being nonsoluble will only wash deeper into the soil along the foundation causing deeper termite prevention. To dress the area up after the oil application you can purchase some stone to put along the foundation which will cover any unsightly oil stained dirt and that can be raked away to re-apply the oil at a later time. To do this with flower beds against a house you need 2 pipes of a length that can be driven into the ground at least 2 feet below the lowest portion of the flower bed. One of these pipes must be slightly longer (1 foot minimum) and be able to fit inside the other. Drive the shorter pipe into the ground till it is at least 2 feet below the base of the flower bed next to the foundation. Then drive the longer pipe into the short pipe leaving the extra length of the pipe extending out of the short pipe. It helps to mark the long pipe so you know when it has been driven equal to the short. A good large pipe wrench will help work the long pipe out of the short. Next pour some oil down the short pipe and give it ten minutes to work its way down the pipe and to soak the ground. Use a piece of rebar (concrete support steel) to push the dirt out of the long pipe. Then pull the short pipe out of the ground and put the dirt out of the short pipe in the hole. Do this every 2 to 3 feet. I've done this the past seven years and have not had any termites since, even though both my neighbors, who have had "professional" exterminators treat their property, have had re-occurances.