Several years ago I was studying Native American herbalism when I learned about Pennyroyal. As a member of the mint family, Pennyroyal got a bad rap because it has a history of being used to terminate pregnancies, and often had harsh side effects. It has even been known to kill when taken in large doses. But my herbalism teacher told me that Pennyroyal would repel fleas.
So I looked it up. The Latin name for American Pennyroyal is “Hedeoma pulegioides”. Pulegioides looked a lot like the Spanish word for flea – “pulga”. Upon further research I found that first century herbalists wrote of Pennyroyal’s action to repel fleas. They probably knew a little something about how plants worked, so I decided to give it a shot.
Due to its toxicity, I had a difficult time finding pennyroyal for sale. But I was lucky enough to find a patch of pennyroyal growing in a field behind my house (in San Francisco) so I helped myself to a nice-sized cutting.
At the time, I kept my two dogs in a fenced dog run in the back yard while I was at work. So I transplanted my newly discovered Pennyroyal along the edge of the dog’s fence. Within a month, the dogs didn’t seem to need a their regular dose of the chemical flea treatment, so I skipped it. I went another two years without having to give doses of the flea-killing compound.
When I moved to Atlanta, I brought my pennyroyal with me (as well as my echinacea and a few other prized plants). But I was sorely disappointed when I moved into a new house and my fresh pennyroyal plantings didn’t seem to keep away the fleas. I had to start using the chemical stuff again as the dogs were getting attacked. Apparently the plants have to be established and it takes time to drive the fleas away (it doesn’t actually kill the fleas, it just makes them want to leave.)
I made several cuttings last fall that over-wintered well and really took off this spring. Now I have several batches of pennyroyal growing in the yard, most notably in an area where my dogs like to hang out in the shade. There have been no signs of fleas. And I haven’t given my dogs chemical flea treatment in months and my house and yard remain flea-free.