Exaggeration, a lot of the time based on folklore. If the essential oils of some are in the air, yes, they may repel some insects. But just putting them in the garden? I don't think so. But I'd love to have one that repels politicians!

I agree with eahamel, doesn't really work just having the plants in the garden. If you are taking bits of the plants and burning them like incense or rubbing on your clothes, perhaps that may work. But cutting down on mosquito habitats like emptying buckets of stagnant water works much better. ;)

FataMorgana

Okay, so the general consensus (both here and from other sources) is that unless I grow an entire bed of these plants and roll in them them daily, they won't do much in the way of pest deterrence. I wonder how much money the big box stores around here are raking in from people who just read the article and ran to the stores rather than doing some actual 'research'.

I use basil leaves to repel skeeters. I rub about 10 leaves in my hands to release the oils, then I rub it on my skin. Haven't been bit yet when I do that.

Leekle, I'm sure they rake in a bunch of bucks from these "urban legends" about herbs. Zack, that's what you have to do to get that insect repellent plant to actually work!

In order for most of these to work they need to at least be made into an infusion and then sprayed on you or the infected plant. My experience with citronella candles, etc. was the same as yours.

An interesting study looks at the ant repellency quality of plants with specific types of floral structures.

Here is a link that might be useful: Ant Repellent Plants

What about citronella plants. Don't they work to repel skeeters?

One herb that actually worked all on its own was Tansy. Just laying some leaves in the cupboard deterred the ants that seems intent on invading any bag or bottle they could sneak their way into.

Here in Texas they sell a system that sends out a fine mist no one in the yard will even notice. I do not know if this works and have not heard any ads lately but the product was called CedarCide, make from the oil of a Cedar tree. But if you put down Cedar chips your helper-lizards may all leave or die off. So far the best thing that has worked for me is keeping grass cut and being in a open area away from trees and bushes. If I find a wet area I drop a drop of dish soap in the water, if you have fish this is not recommended, and they will be more than happy to keep the mosquito larva down.