its funny you posted this request here, as about a week ago, i was hearing on the news about a company who ended up with a bed bug infestation that took thousands of dollars for them to get rid of.
so, i began to think, "what natural remedies would help to keep them away?" and of course--did a google search!
here is what i found--on this site:
http://www.ehow.com/about_5220833_herbs-rid-bed-bugs.html
Herbs That Can Help
Many people are reluctant to use poisons and pesticides in and around their homes. Fortunately, certain herbs and other natural products such as black walnuts are effective in ridding your home of bed bugs and keeping them away. Natural products that repel bed bugs are available at many natural foods stores. Look for those that contain black walnut or garlic. Cayenne pepper drives them away, and pleasant-smelling mint is also effective in repelling bed bugs. Lavender is another pleasant-smelling herb that bed bugs do not like. Spray or spread one or more of these herbs on top of your mattress and then cover it with a freshly washed mattress pad and sheets, blankets and bedspread.
i know garlic and onion juice diluted in water is great for a lot of bugs--keeping them away. however, it's not exactly a remedy you'll want to use inside the house-as the smell is not very nice. but remember this for your garden in spring and summer. it helps against beetles, mites and other bugs as well as rabbits too, I think. and sprayed on your grass all around your home, will also keep mosquitoes away. cayenne pepper is okay--as it is not so pungent smelling. but the mint and lavender is much more to my liking! and mint is also a remedy for keeping mice, moths, ants and flies at bay too. I also believe they will keep away mosquitoes.
Although not an herb, aturally occurring pyrethrins mixed with canola oil can help greatly in bed bug control.
Other Methods of Controlling Bedbugs
If you have an infestation of bed bugs and don't want to replace your mattress and other bedding, you can purchase special covers that trap these insects inside your mattress, box springs and pillows. These covers are also said to be effective for controlling dust mites. Made of a special fabric that bed bugs cannot get through or bite through, these covers can cause the eventual death of the insects that are living inside your mattress.