Catnip (Nepeta cataria)
This perennial member of the mint family is native from eastern Europe eastward to China. It is a bushy, branching herb that grows to 50–100cm (20–39″) tall. Like many mints, its stems are square in cross section, and its leaves have a soft texture, being covered by minute hairs. Its white to pale-pink flowers are highly attractive to bees, butterflies, and other pollinators. Catnip is hardy to Zone 4, and works well in containers.
Catnip has been celebrated for centuries as a medicinal herb, and it has come to be known by many names: Catmint, catnep, catrup, catswort, field balm, or, simply, nep. The word Catmint is now generally used to describe all members of the genus Nepeta, including the ornamental flower, but we are focused here on N. cataria.
Various early herbalists expounded on its medicinal properties, but none, perhaps, with greater enthusiasm than Nicholas Culpeper:
Nep is generally used for women to procure their courses, being taken inwardly or outwardly, either alone, or with other convenient herbs in a decoction to bathe them, or sit over the hot fumes thereof; and by the frequent use thereof, it takes away barrenness, and the wind, and pains of the mother. It is also used in pains of the head coming of any cold cause, catarrhs, rheums, and for swimming and giddiness thereof, and is of special use for the windiness of the stomach and belly. It is effectual for any cramp, or cold aches, to dissolve cold and wind that afflict the place, and is used for colds, coughs, and shortness of breath. The juice thereof drank in wine, is profitable for those that are bruised by an accident. The green herb bruised and applied to the fundament and lying there two or three hours, eases the pains of the piles; the juice also being made up into an ointment, is effectual for the same purpose. The head washed with a decoction thereof, it takes away scales, and may be effectual for other parts of the body also.
Catnip is best known for its curious effect on cats. Most cats respond to its scent (and taste) with kitten-like behaviour, drooling, sleepiness, purring, anxiety, and apparent excitement. The Elizabethan herbalist Gerard noted:
They do call it herba cataria and herba catti because cats are very much delighted herewith for the smell of it is so pleasant unto them, that they rub themselves upon it and wallow or tumble in it and also feed on the branches and leaves very hungrily.
The plant contains the organic compound Nepetalactone, which was first isolated in 1941, and acts as a cat attractant. And it causes these amusing responses in nearly all felines, including leopards, cougars, and lynxes. Among domestic cats, it is estimated that around 33% do not not respond to catnip in any noticeable way. This is thought to be an hereditary trait.
Happily for gardeners, the plant also contains the compound Iridodial, which attracts lacewings, one of the top beneficial predatory insects. Extracts of Nepetalactone can also be refined to form strong fly and mosquito repellents. Nepetalactone is best extracted through steam distillation.
Catnip can be brewed into a relaxing (even soporific) tea, or used as a culinary herb. Some fresh leaves might be sprinkled over a salad, or served with other bright herbs to be eaten in salad rolls. The flowers are edible, and their dainty size makes them quite suitable as a topping for salads or savory cakes.
The Catnip Festival was “London’s First Cat Video Festival,” held in November 2016, as a fundraiser for the Battersea Dogs & Cats Home. The annual event promises “a massive night of bangin’ caterwauling mewsic, cat-ivities, and fierce feline performers!” Cat videos can be uploaded to their website to be judged in the cat-egories: Best Singer, Mightiest Action Hero, Cutest Catnap, Most Cunning Saboteur, and Greatest Acrobat.
How to Grow Catnip
Difficulty: Easy. Catnip seeds have uniform germination, and it is suitable for container growing.
Timing: Sow seeds indoors in February and March, and transplant or direct sow in April and May. Can also be direct sown where it is to grow in September. Bottom heat will speed germination.
Sowing: Sow on the soil surface or barely covered with perlite. Thin plants or transplant to 30cm (12″) apart. Keep seedlings well protected from cats!
Soil: Catnip will grow in nearly any garden or container soil with good drainage.
Growing: Catnip does very well in containers, raised beds, or borders in full sun to partial shade. The main challenge to growing it is protecting it from cats. After the main bloom, plants should be cut back hard to encourage a second bloom and tidy shape.
Harvest: To save the summer catnip bounty, harvest when fully grown, including some flower stalks, and keep the plant picked regularly.
Storage: Stalks can be hung in an airy place out of direct sunlight until fully dry. The leaves and flowers can then be removed and stored in zip-top plastic bags, airtight containers, and so on.
Seed info: Ideal temperature for germination: 21-27°C (70-80°F). Seeds should sprout in 10-20 days. Usual seed life: 5 years.
Pests & Disease: Cats are the main cause of damage to catnip plants and plantings. No, seriously.
Companion Planting: Catnip attracts lacewings to control aphids and other garden pests. It also attracts parasitic wasps, and numerous pollinators. Catnip repels aphids, asparagus beetles, Colorado potato beetles, and squash bugs. More on Companion Planting.
