Taxonomy and Botany of Catnip Plants
Plant taxonomy classifies catnip plants as Nepeta cataria. Note that the common name, "catmint" is preferred in the U.K. As a result, it may be tempting to use the two names interchangeably. But in the U.S. we tend to reserve "catmint" for the ornamental relatives of N. cataria, such as Nepeta x faassenii and Nepeta mussinii. Where the latter are referred to below, the scientific name is used, in order to avoid confusion with the main subject of this page, which is N. cataria.
Nepeta cataria plants are classified as herbaceous perennial herbs. Catnip plants have naturalized in parts of North America. Even where they are not perennial, they will likely reseed. In fact, some of you may find catnip too weedy and too aggressive a spreader to grow it in your landscape.
Features of Catnip Plants
Catnip plants can attain a size of 3 feet tall and 3 feet wide. Their small, white or lilac-colored flowers grow in clusters. The stems of these fragrant plants have the squarish shape typical of the mint family (to which they belong), whether herb or weed (creeping Charlie, for instance). Catnip plants enjoy sun and are drought-tolerant ground covers, making them a good choice for sunny, dry areas where many other plants would struggle. But they offer little ornamental value. Nepeta cataria is the preferred herb to grow for cat-lovers; fewer cats are attracted to the ornamental types, such as Nepeta mussinii.
Native Origin, Planting Zones, Sun and Soil Needs
Native to Eurasia, catnip plants can be grown in North America in planting zones 3–9.
Grow them in full sun to partial shade. Like so many herbs, this perennial thrives in poor soil that is well-drained. Catnip plants prefer a slightly alkaline soil but really are not very fussy about the ground in which they grow as long as their roots are not constantly sitting in water.
Care Tips: Pests, Pinching, and Drying
Unless you can tolerate damage from unwelcome neighborhood cats, protect these herbs by, for example, fencing them off. You should not have to protect them from insects and rodents, as few of these pests are drawn to catnip. That is a good thing, because you would not want to apply poisons to the plants to keep such pests away, since you want to be giving your pets a safe, healthy harvest to enjoy.
Pinch them often while they are growing, to obtain dense, well-shaped plants. You can do the same with the related ornamental plants in the genus, such as 6 Hills Giant catmint (Nepeta x faassenii '6 Hills Giant'). This practice will prevent them from getting too big and give you nice, bushy herbs.
Harvest them upon flowering, on a dry, sunny day. Late morning is a good time to harvest, after the dew has dried but before the day heats up. Cut off the whole plant at the base, and hang it upside down, as soon as possible, in a dark, dry, well-ventilated place (for example, an attic). Store dried leaves, stems, and flowers in freezer bags to preserve the potency of the oil inside them. Following these steps will allow you to minimize loss of this oil, which is the stuff that makes your cat go wild.
Uses in Landscaping
The catnip plants discussed here (Nepeta cataria) are grown mainly with cats in mind. As part of the "cat-friendly yard," grow them:
- For your cats to enjoy outdoors.
- To cut fresh stems to bring to your pets indoors.
- To harvest them to dry them for future use.
But if you are more concerned with your landscape design than with your cats, grow ornamentals such as Nepeta mussinii, instead. The latter is a more attractive herb, as it stays shorter (1 foot tall). Nepeta mussinii has a spreading habit and is used as a ground cover. Both Nepeta mussinii and Nepeta cataria are deer-resistant but do attract butterflies.
Uses in Food and Medicine, Psychoactive Properties
These perennials are not just for cats. Like so many herbs, they also have uses in food and medicine, whether used fresh or dried.
People have traditionally drunk a tea made from the leaves and flowers to relieve coughs, for example. The leaves and shoots can be used as ingredients in sauces and soups. The oil extracted from catnip plants is even used in natural mosquito repellents.
But these uses are not what we mainly think of when we hear mention of catnip. What most people are interested in are the psychoactive properties that catnip plants can have on cats when they are eaten or when their fragrance is inhaled by cats. Simply smelling catnip is, in fact, often enough to cause cats to react to it, which is why you will sometimes see them rolling in it. The resulting drug "trip" comes courtesy of a chemical named "nepetalactone."
The impact is not the same on all cats. The reaction is inherited, and only some are sensitive to nepetalactone. Other cats will turn up their noses when presented with the plant (whether fresh or dried). Even some of the big cats are affected by it.
Cats that react to catnip will generally respond not only to the leaves, but also to the flowers and stems. And do not worry: "Nepetalactone is not addictive or harmful for cats," says one expert in veterinary medicine.
Invasive Nature and How to Cope With It
While you can give your cats the green light to eat catnip, one can't issue an "all clear" signal when it comes to using it in your landscaping. Catnip plants may be considered invasive plants. They will spread out of control unless you take measures to keep them from doing so (which means extra work for you). Only you can decide whether or not the benefits of the herb outweigh this drawback.
The plants will reseed all over your property if you let them, meaning that you will have new plants springing up in unexpected places for years to come. For this reason, if you like a tidy landscape, you may come to regard catnip as more of a weed than an herb. But a way to compromise and have the best of both worlds is to prevent the plant from blooming (no flower means no seed): Simply pinch off the top of the plant when flowers start to form.