The Cat Garden Guide

Although cats are obligate carnivores, they still consume some plant matter and rely on plants in many other ways. Cats may eat or chew on a variety of plants for fiber, added nutrients, or even zoopharmacognosy. This post attempts to dive into cat nature and ecology to gain insights into what those plants might be and how we can use that knowledge to build the perfect cat garden!

Cat domestication is a complex topic of research. Current research suggests that there were two major periods of cat domestication. Once in Southwest Asia, around 10k years ago, and once in Egypt around 4k years ago. But cats have also interbred with wildcats (Felis silvestris lybica or F. lybica) throughout Africa and Eurasia, so it's very difficult to pinpoint what their original habitats were like. But looking at the ranges of its wildcat ancestors can still give us clues about the flora ancestral cats might've interacted with and relied on.

I've come up with three categories of plant usage by cats and listed some examples of plants that might be good fits for cats. I've also attached some additional resources at the end of this post if you'd like to do your own similar research.

1. Catnip, silver vine, and other mosquitto repellents

That euphoric reaction cats exhibit after being exposed to Catnip (Nepeta cataria, aka catmint) is due to a chemical called nepetalactone. However, this chemical doesn't just exist in Catnip, but also in most other plants in the Nepeta genus. In fact, it's found in some other plants in the mint/sage family (Lamiaceae). And it's even found in totally unrelated plants like Valerian Root or Tartarian Honeysuckle from the honeysuckle family (Caprifoliaceae). In fact, it's not even the most effective at triggerring this response.

When you look up alternatives to catnip, you'll usually come across 3 plants mainly: Valerian Root, Tartarian Root, and Silver Vine. The reason these always show up goes back to a study that tested the effectiveness of these plants compared to Catnip. It found that Tartarian Honeysuckel and Valerian Root both triggered this response in about 50% of cats while Catnip affected 66% and Silver Vine came out to 80% (among cats that weren't affected by catnip, this percentage was actually even higher!). Because veternary science in general is seriously underfunded/understudied, studies like this tend to have an outsized effect. But these four plants are far from the only plants that could potentially trigger this response.

Besides looking at other plants known to contain nepetalactone (e.g. Paeonia anomala or other catnip species like Dwarf Catnip), there's a lot of cultural knowledge of potentially even more potent plants that has yet to be studied formally:

• The effects of Kuppaimeni (Acalypha indica) on cats is widely known throughout much of India. It contains nepetalactones and iridolactones which are widely said to cause a reaction much stronger than catnip
• Lemongrass (Cymbopogon citratus) is often said to have catnip-like effects on cats. I've seen this claim through numerous online articles, but haven't yet been able to track down the source for it. It is also used in cooking in many cuisines and traditional medicines throughout the world. It is known to repel stable flies (and likely other insects).
• Silver Vine (Actinidia polygama), a plant in the kiwi family that is native to parts of Korea, China, and Japan, is one of the few plants whose effects on cats, though known widely by local people, has been formally studied. It affects about 4 in 5 cats compared to the 2 in 3 that are affected by catnip. Its edible fruit and other plant parts have been used culinarily, medicinally, and for other purposes for a long time.
• Cat thyme (Teucrium marum) is also a common alternative to catnip. It is in the mint family as well and likely contains nepetalactones.

Why are they so into it?

Catnip, like many of the plants mentioned above have also been known for a long time as insect repellents. A 2021 paper published in Science Advances argued for the hypothesis that the reason cats have this reaction, which causes them to rub themselves against the plant, likely has a lot to do with getting the insect-repelling chemicals on their fur to repel mosquitoes and other insects that may transmit feline diseases.

2. Catgrass!

Cats graze on grass for many possible reasons. It might be for the folic acid, which helps the blood carry more oxygen; they may be using it as a laxative; it may be to help with sore throats; it may be for the emetic properties (sometimes cats eat indigestible things and need help puking them back out); or it might just be because they enjoy the texture! Regardless of the reasons, grazing on grass is a common and healthy behavior for cats.

When you look up "catgrass" you'll like come across a few different species. Usually the word is just used to refer to grass that cats can safely eat (most grass) and in those cases you'll probably either find wheat seeds or a blend of wheat, barley, oat, and rye grass seeds (oat seems to be the most commonly beloved of those). Alternatively, "catgrass" could be referring to Dactylis glomerata which is native to temperate Eurasia and Northern Africa. It's often used as hay because of its high yields and high sugar content.

Most grasses are best grazed when young and tender, but become too course to be grazed on once they mature.

3. Nutritious herbs

Other plants cats like to snack on are often high in minerals and nutrients important for their health. Parsley, carrot tops, and spinach are common favorites that are great sources of vitamins A and C and many other vitamins and nutrients. Cats also like to snack on many edible flowers like zinnias, marigolds, and johnny-jump-ups. Cats have also been known to munch on rosemary, beans sprouts, and even alfalfa sprouts (note that alfalfa is a hyperaccumulator of many heavy metals in the soil). Garden mint can also be eaten, but can be toxic if large amounts are consumed (the same is actually true for catnip). However cats don't usually eat mint, but rather just roll around in it like they do with catnip. A safer mint species could be lemon balm, common sage, lavender, or even rosemary (yes, these are all in the mint/sage family).

Plants to avoid

Although this article points out specific species which are known to be safe or unsafe to eat for cats, cats don't usually check for a scientific identification of a plant before munching away. Cats, like many other animals including humans, tend to just chew on the tender new growth of many different plant species that don't exhibit any obvious signs of toxicity. New growth in plants is usually the least likely to contain toxic compounds which is why we're able to get away with eating vegetable greens like spinach which may otherwise be toxic or unpalettable if eaten after they've matured. However, this isn't fullproof and cats do can make mistakes. There are certain herbs, as well as houseplants, that are known to be harmful to cats and should be avoided.

There are a few plants that are highly toxic and even small amounts could be life-threatening. Here's a partial list of some of the most common culprits:

• Amaryllis (Amaryllis spp.)
• Autumn Crocus (Colchicum autumnale)
• Azaleas (Azalea spp.) and other plants in the Rhododendrons family
• Castor Bean (Ricinus communis)
• Cyclamen (Cyclamen spp.)
• Daffodils (Narcissus spp.)
• Easter Lillies and most other plants in the Liliaceae family.
• Oleander (Nerium oleander)
• Tulips (Tulipa spp.)
• Sago Palm (Cycas revoluta)