CP's won't put a dent in the flea population, unless maybe you had a million sundews and butterworts. Even then, I wonder if they would be even attracted by them. Any catchings would likely be accidental. You have to go proactive in order to get rid of them. I admire your desire to go natural. Are you trying to get rid of them inside a house, or in your yard? Pyrethrins are a natural insecticide that will help somewhat, as well as frequent washing of bedding, floors, etc. In my experience though, you have to get something that disrupts the life cycle to truly eliminate them. We had a bad infestation several years ago, through our dog. Frequent bathings with a pyrethrin shampoo, washing the floors, bedding, etc. didn't really do much. It wasn't until we got that stuff that makes the eggs not hatch, or something to that effect, that the problem was eliminated. It is a safe product, not a poison. Can't remember how it works, but it makes the eggs infertile or something like that. They are a tough critter to get rid of.