The need for feline repellents goes back as far as humans have kept domesticated cats. Whether it's your own kitty chomping on your indoor plants or a stray digging in your garden, keeping them from making messes where people don't want them has been a continuing battle. For those who prefer natural remedies, there are traditional nostrums and some new wrinkles in the war, all claiming success in keeping kitty out of where she's not welcome.
Cats have sensitive noses, so a natural way to keep them away is with a smell that repels. Citrus is a natural cat repellent so spread orange or lime peel around gardens or in indoor plant pots to keep cats away. Other deterrents include coffee grounds, blood meal, ground ginger and cayenne pepper. Oils are popular, including lavender, lemon grass, citronella, peppermint and eucalyptus. To make your own deterrent, mix equal parts vinegar, liquid soap and water and spray in gardens, croquet pitches, putting greens and indoor pots. Apply regularly until the cats learn it's not going away.
New "Scaredy Cat" Plant
A new weapon against feline invasions is Coleus Canina, a plant that cats, dogs and even foxes will avoid. Nicknamed "Scaredy Cat," it is an attractive annual garden plant with grey/green foliage and blue flowers that don't bother humans, but cats can't stand its smell. It grows in full sun or partial shade and requires protection from frost or can be grown from cuttings kept over the winter.
A layer of gravel or spiky pinecones on your garden can make the area less attractive to soft kitty paws. For indoor plants, inserting rows of sticks into the soil with an inch or two exposed will make squatting uncomfortable for cats. Cats also startle easily. Scattering water bottles in the garden at angles that will reflect random light flashes can scare them away.
Some commercial repellents use animal instinct as their weapon. Cats are the smallest of the Felidae family. Adding the faeces of lions or urine of coyotes to sprays or pellets acts as a warning to wandering kitties that a dangerous predator has moved in. Mark the territory you want to protect and cats should steer clear of any confrontation. These last several months, but should be replenished regularly and after heavy rains.
Mothballs used to repel cats are a pesticide. The naphthalene they contain is toxic to children as well as cats, wildlife and beneficial insects. The EPA links short-term exposure of humans to naphthalene to cataracts, liver and neurological damage. Also be careful of cayenne or other peppers sprinkled on garden or potting soil can be picked up by children or your own pets and transferred to their eyes or mouths, which is quite painful.
Rue (ruta graveolens), a popular blue leafed garden shrub, has a history of medicinal uses as well as use an insect and cat repellent, but it is a serious toxic irritant when it comes in contact with human (and animal) skin in sunlight.