Catnip, known by it's botanical name of Nepeta cataria, is a perennial groundcover growing two to three feet high that is part of the mint family. Though it's commonly referred to as catmint as well, catmint is actually a different variety of nepeta, Nepeta faassenii, which grows in soft mounds of two feet in height.

Catnip is well-known for its effect on cats. After inhaling catnip, many cats enter a trance-like state characterized by extreme playfulness and pleasure. Though you may observe your cat nibbling at a catnip plant, he's most likely only doing so to release the odor since the catnip reaction results from inhaling the plant rather than ingesting it. Cats will vary in the intensity of their response, and some 30% of cats won't respond at all to catnip. That's because a cat's responsiveness is inherited. Further, it's often described as a ‘catnip gene' that some cats have while others do not. Cats who do have the gene usually don't respond until they've reached the age of six to eight months.

Catnip is believed to have first been given to cats by the Ancient Egyptians, who worshipped cats. It has historically been used for other purposes too, including in cooking and in the treatment of colds, nervousness and gastrointestinal problems. It grows throughout North America .