Cockroaches are a common household pest that's difficult to get rid of. Traditional methods of roach control often involve toxic pesticides. However, in homes with young children or pets, these techniques may not be appropriate. Some natural remedies derived from plants and flowers also work to repel roaches. While no plant or plant extract can replace good home hygiene, regular cleaning and eliminating food sources, they may help discourage a roach infestation.
According to Science Daily, placing catnip around the house can discourage roaches. Two forms of a chemical called nepetalactone, which are found in the catnip plant, may repel cockroaches. When given a choice between a surface treated with catnip oils and one which was untreated, German cockroaches preferred the untreated surface, and spent more time there. According to Iowa State University, roaches will actually walk away from the treated surface. Catnip is a non-toxic, aromatic herb in the mint family, and is relatively simple to grow at home.
Another plant, osage orange, was also studied at Iowa State University. Osage orange is a tree native to North America, and is sometimes called the hedge apple. It has a long folk history of use as an insect repellent. Three compounds in osage orange oil have been identified as repellent to cockroaches. These trees are relatively common in the American Midwest, and produce a large, wrinkled, inedible fruit which eventually turns bright yellow or orange. According to the Great Plains Nature Center, the tree is easily grown from seed. The oil in crushed osage orange fruit may work as a home cockroach repellent.
The leaves of the bay laurel or sweet laurel are commonly used in cooking, but they may also have cockroach-repellent properties. Bay leaves contain a number of essential oils, including terpenes and eucalyptol, an ingredient in some insecticides and insect repellents. According to Herbs 2000, this plant is traditionally used to repel insects from silos and other food storage areas. Aerias Air Quality Sciences suggests placing bay leaves in all cabinets, the pantry and on shelves to repel these insects. Fresh bay leaves tend to contain more essential oils than the dry variety, but dry leaves may be used if fresh ones are not available.