Nepeta cataria.
Not to be confused with cat grass (Avena sativa), oats grown as young shoots that domestic cats like to nibble for fibre and folic acid. This, by contrast, is the psychoactive herb that makes them roll, rub, and drool in ecstasy.
The herb with a thousand roles: first for domestic cats, who lose all dignity as soon as they smell it, but also for humans, who have made a soothing tea from it since antiquity, and for gardeners, who appreciate its spectacular insect-repellent power. The scientific name Nepeta cataria already says a great deal: according to Pliny the Elder, Nepeta comes from the name of the Etruscan city of Nepete (present-day Nepi in central Italy), where the plant was particularly abundant in antiquity; cataria derives from the Latin cattus ("cat"), for obvious reasons.
A member of the Lamiaceae family (like mint, lemon balm, and sage), catnip has been cultivated in Europe and Asia since antiquity. Dioscorides mentions it as a digestive and calming remedy, and European settlers brought it to North America in the 17th and 18th centuries. It quickly escaped from gardens and became naturalized everywhere, including Québec, where it is still regularly found along country roads, on old abandoned farms, and in pastures.
A robust perennial growing 60 to 90 cm tall, with the square stems characteristic of the Lamiaceae and oval, toothed, slightly downy leaves in a somewhat silvery grey-green. In summer, spikes of small white flowers speckled with purple attract large numbers of bees and bumblebees. Its famous effect on cats comes from a particular volatile molecule, nepetalactone, which curiously mimics feline pheromones. About 65 to 70% of adult cats react to it; for the others, it is genetic. Kittens under six months never react. The typical effect lasts 5 to 15 minutes: ecstatic rolling, compulsive rubbing, salivation, and then a phase of gentle bliss. It is completely harmless and non-addictive. Surprisingly, big cats react to it too, including lions, tigers, and panthers.
For people, a light infusion (1 teaspoon dried herb per cup, steeped for 5 minutes) has traditionally been used as a soothing bedtime tea or for difficult digestion. In modest doses, the effect is gentle and relaxing, with no particular psychoactive effect. For gardeners, nepetalactone is also a powerful natural mosquito repellent. A 2001 Iowa State University study measured it as being up to ten times more effective than DEET (the synthetic compound in conventional mosquito repellents) in equal quantities. A few crushed stems carried in a pocket or rubbed on the skin effectively repel black flies and mosquitoes in hot weather, which is useful when working outdoors in summer.
Grower's tip: Do not confuse it with ornamental "catmint" (Nepeta × faassenii, Nepeta mussinii), a relative grown mainly for its decorative blue flowers that has no effect on cats. Nepeta cataria is true catnip. Start indoors 6 to 8 weeks before transplanting, or direct-sow in late May in Québec. Germination can be erratic; the seeds benefit from cold stratification (two weeks in the freezer in a sealed bag) before sowing. Once established, the plant self-seeds generously (sometimes too generously) and remains perennial for decades. To harvest, cut flowering stems in full bloom, tie them in bunches, hang them upside down in a shaded, dry, well-ventilated place for 2 to 3 weeks, then strip the leaves and store them in an airtight jar.
Note: if you are growing this plant for a cat, it is best to keep it out of reach until harvest. Otherwise, the cat will trample, chew, and flatten it to the ground long before you can harvest a single leaf.
- Open-pollinated. Hardy perennial, zone 3. Insect-pollinated; crosses with other Nepeta (rare in vegetable gardens), so there is little risk of crossing.
- Height: 60 to 90 cm.
- Bloom period: June to September.
- Exposure: full sun; tolerates partial shade.
- Well-drained, rather dry, moderately rich soil. Very undemanding; tolerates poor, stony soils.
- Start indoors 6 to 8 weeks before transplanting (cold-stratify for 2 weeks beforehand), or direct-sow in late May. Self-seeds abundantly once established.
