A cat-alyst for feline joy

Whether your cat likes it or not, catnip is an appealing, flowering herb and grows well in a pot.

Catmint and catnip plants are beautifully fragrant in the summer garden

I'm always delighted when I come across a piece of information that supports my affection for cats. This week I found the piece de resistance: one of the most famous gardens in the world, the 435ha Longwood Gardens in Pennsylvania, actually has cats on the payroll.

More than a dozen cats are employed there as members of the gardens' integrated pest management team, and they patrol all of Longwood's grounds, from the nursery and the Peirce-du Pont house to the Abbondi composting facility. Gareth Morgan, eat your heart out.

Each cat has an assigned area of the garden, and a human caretaker. The responsibilities these felines take on are varied. Their primary job is on the rodent control task force, dealing to voles, mice, rats and chipmunks, but they also work as greeters, work supervisors, lap warmers and highly skilled catmint pruners. They toil in exchange for food, shelter, and a health-care plan that includes annual check-ups and vaccinations and emergency treatment when required.

I discovered all of this in the course of investigating the demise of my catnip plant. Astonishing what you find when you type the word "cat" into Google. The absence of catnip has had a profound effect on our brain-damaged cat, who has been in the habit of spending most of her day lying on it, so it has to be replaced. I'm ashamed to admit that it died of thirst: we recently had a roof built over the pergola, cutting off the supply of rainwater to the pot plants. Luckily the catnip was the canary in the coalmine and I managed to rescue the rest of the herbs and two dwarf lemon trees before they went the same way.

Catnip, aside from its mind-altering properties, is a really pretty plant and I'd grow it even if I didn't have cats. Its proper name is, appropriately, Nepeta cataria, and there's also catmint, (Nepeta mussinii). Both are easy to grow in full or part sun and well-drained soil. Catnip grows about 30cm tall and produces tiny lavender flowers in summer. It's said to be a rat deterrent, although at our place it's probably the stoned tabby lying on it that deters the rats.

Catmint can grow up to 90cm tall and has small white or lilac flowers in summer. Both are beautifully fragrant in the summer garden.

It's said to be a cat repellent, but Coleus Canina, a member of the mint family, may be better at attracting bees and butterflies (above)

Most domestic cats respond biochemically to nepetalactone, the essential oil in catnip and catmint. It induces harmless physiological reactions, including psychosexual responses in both male and female cats, which is why it is considered an aphrodisiac. Some of the large cats, including cougars, bobcats, lions and lynx, also respond. Happily, you're not likely to have to deal with a stoned, sexy bobcat rampaging through the garden, (although a cougar may be a different story).

So you can safely grow catnip for your cats, but never fool yourself that it will keep them from digging up things you've just planted somewhere else. Cats can spot 25 baby Mondo grasses at 100m and will be upon them before you've put the trowel down.

If marauding felines are an issue, especially now that spring is here and you'll be planting, there are several natural cat repellents that are safe and easy to use:

• Spray a vinegar-and-water solution around the base of your acid-loving plants.

• Put lemon and orange peels around your plants.

• Surround new plants with pebbles or gravel.

• Plants such as the scented geranium, the mosquito plant, and citronella will deter cats.

There's a garden myth that a plant called Coleus Canina, nicknamed "Scaredy Cat", will keep cats, dogs and practically everything else away, but the jury is still out on this.

The plant is not actually a member of the coleus family - it's an attractive perennial herb and a member of the mint family. It has a strong, unpleasant scent triggered by touch or the sun, and pretty blue flowers from spring until the early frost. It's easy to grow as the leaves will root within a few days of touching the soil.

To propagate, cut the leaves in half and plant them, cut side down, into fresh potting soil. Keep the soil moist and you'll have a large batch of rooted herbs in a few weeks. Transplant the baby plants into full sun or partial shade, into containers. Place the pots where you've planted new seedlings and test the deterrent theory. Even if it fails the test it's sure to attract butterflies and bees, which is just as useful as deterring cats, I reckon.