Can Plants Really Repel Cats and Dogs?

Standard
20180418A big5kayakchallenge.com & domobfdi.deviantart.com

In fact, cats and dogs really don’t seem to be bothered by so-called repellent plants. Read on to learn why. Source: big5kayakchallenge.com & domobfdi.deviantart, Montage: laidbackgardener.com

There are lots of blogs and articles on the Internet promoting repellent plants, plants that are supposed to keep cats and dogs away from the garden just by their smell. It’s a most interesting concept, because sometimes our furry little friends do cause a lot of damage in the garden … but do animal-repellent plants actually deliver the goods?

The idea usually promoted is that you simply have to plant repellent plants here and there throughout a flower bed or vegetable garden and then mammals (it seems to be mostly cats that people want to expel*) will then avoid the sector. It’s a concept as old as the world … and yet, positive evidence on the subject rare; I’d even say nonexistent. Many claims, little evidence? That’s not usually a good sign!

Lack of Studies

I have seen zero serious studies on the subject. Not one! There are many about essential oils derived from plants and used to repel insects, but that’s a different story entirely. I was looking for proof that planting certain plants in a garden setting would keep pets away … for an entire season, if not longer! Instead, I found lots of sites claiming this works, but offering no proof whatsoever. Most just seem to take it for granted that repellent plants work, repeating what the author has read elsewhere. On the few sites when there did seem to be some sort of proof, either positive or negative, it always seems to be purely anecdotal, like: “Well, I grow plant X in my garden and I don’t have a cat problem.” Yes, but neither do many gardeners who don’t knowingly grow repellent plants.

20180418H wallpaper.applegreetings.com.jpg

“Nope! No cats in my garden!” Source: wallpaper.applegreetings.com

Most positive posts were from people who tried planting repellent plants as a preventive measure (there were no cats visiting their garden, but they wanted to keep them away) and they’re the first to claim victory. “I planted plant X and no cats have come, so it must have worked!” Obviously, that proves nothing. Maybe cats simply have no reason to visit that garden? Or the owner is not looking at the right time?

Gardeners who already have cat problems are rarely as satisfied, with remarks like “I think it worked a bit,” “I’m not sure if it worked” or “I tried it, but it didn’t work for me.”

Even if you turn to sites hosted by veterinarians, where you think there would be something more concrete, you find a mix of responses. Some simply list repellent plants, but offer no proof, and a few seem to take a more studied look at things and suggest that some plants might have repellent characteristics, but at short distances. Usually, 6 to 8 inches (15 to 30 cm) is the distance given. Essentially, therefore, cats and dogs would only react to repellent plants when they’re right next to them.

My Experiences

A few years ago, I tested a few of these plants on my own pets: my cat Geisha (may she rest in peace) and my dog Maggie, just for the fun of it. This was hardly a scientific study. There were no controls and—who knows?—maybe my pets are just less reactive to scented plants than others? Or trusting of me? Still, I must admit the experiences didn’t lead me to think very favorably about animal repellent plants!

The Piss-Off Plant

20180418B www.heimhelden.de

The famous Piss-Off Plant (Plectranthus caninus) is more likely to piss off gardeners than cats. Source: http://www.heimhelden.de

I got into this years ago when a plant new to me came onto the market as a cat- and dog-repellent. Called by various trade names, including Scaredy Cat™, Piss-off Plant™, Dog’s Gone™ or Bunnies Gone™, it was said to be Coleus canina, It didn’t take much digging to discover its real name is Plectranthus caninus: an honest mistake, as the two plants are closely related. Its promoters claim it will keep dogs, cats and other mammals (raccoons, rabbits, etc.) at bay.

One seller even invented a detailed background for the plant, claiming it’s a hybrid developed by an Australian amateur gardener by crossing a plectranthus with a coleus, although, in fact, Plectranthus caninus has been growing wild in Africa and India for hundreds of thousands of years. Moreover, when one seller tried to get a patent for this plant (under the name Sumcol 01), the request was denied on the grounds that “the plant presented no discernible difference from the species.”

Despite its unpleasant odor, released when you brush against or stroke the plant’s sticky foliage, there is no evidence that cats, dogs or other animals are in the least disturbed by the presence of Plectranthus caninus. I added one next to Geisha’s favorite sunbathing spot and she just ignored it. In fact, she’d often lean against it when she slept. Nor did she react if I held a cut branch in front of her. I rubbed a leaf with my fingers and held them in front of her muzzle, she did pull her head back, but then, Geisha never did appreciate anyone invading her personal space.

As for Maggie (the dog), she was harder to test, being naturally more excitable, but seemed to show no special reaction when I held a branch in front of her. Placing a pot next to her water bowl didn’t dissuade her in the least, but she did sniff my fingers more willingly than Geisha after I had rubbed the leaves and didn’t seem put off.

My conclusion based in this very limited test what that Plectranthus caninus has no repellent powers whatsoever … on my pets!

The Do About Rue

20180418C www.researchgate.net

Rue (Ruta graveolens) is pretty enough, but potentially harmful to humans … and doesn’t seem effective as a cat repellent. Source:www.researchgate.net

I tested rue (Ruta graveolens) at the same time. According to popular belief, it will keep away cats away from the garden, but when I placed Geisha next to the plant growing in my flower bed, she ignored it. I put on latex gloves (rue is phototoxic to many people and should be handled with great care) and tried dangling it front of her nose as she slept. Again, no reaction. Maggie just ignored it as well.

With rue, the question you really have to ask is whether you want to risk causing grievous bodily harm to your family in a probably futile effort to keep cats away? I no longer grow rue since a friend of mine had a painful reaction after brushing against one … in my garden!

Lavender

20180418D www.localharvest.org.jpg

People love the smell of lavender, but cats seem indifferent to it. Source: www.localharvest.org

Humans consider the scent of lavender (Lavandula spp.) delightful, but it’s actually a natural repellent. The plant produces it to repel insect pests and grazing mammals … but the scent itself isn’t really what keeps them away: it’s the bitter compounds in the leaves that insects and certain mammals avoid. Some websites suggest that lavender will repel cats, but certainly neither of my pets minded it at all. Also, feral cats sometimes cause damage in commercial lavender fields, suggesting lavender has little effect on cats indeed.

Marigolds

20180418E www.solitarywanderer.com.jpg

Clearly this cat is not bothered by African marigolds (Tagetes erecta). Source: www.solitarywanderer.com

I tested marigolds (Tagetes spp.) at a later date, because I had not heard it was supposed to have repellent effects, at least not on mammals.

Different marigolds have different scents, some attractive to people (T. lucida and T. minuta), others distinctly unpleasant (T. patula and T. erecta). These odors are all designed to repel insects, or at least, to keep them from eating the plants. You see, the plant really doesn’t want to repel insects: it needs pollinating ones to ensure its flowers are fecundated. In fact, marigolds are widely used in companion planting to attract pollinating insects. It only wants to keep insects from eating its leaves. So its taste is repellent; its scent, not so much.

Geisha and Maggie both found marigolds (I tried T. patula, T. erectato and T. minuta) be of no interest whatsoever and were neither rebuffed nor attracted by them.

And the Others

20180418F flipper.diff.org.jpg

The curry plant (Helichrysum italicum) smells like curry and that doesn’t seem to bother cats. Source: flipper.diff.org

I suspect that, if any plant that has a scent, somebody somewhere will eventually claim it repels cats (and maybe dogs). Here are some other plants that have that reputation, but didn’t work on my pets: curry plant (Helichrysum italicum), rosemary (Rosmarinus officinalis) and pennyroyal (Mentha pulegium). I also tried a few of the many lemon-scented plants—lemon balm (Melissa officinalis), lemon-scented pelargonium (Pelargonium crispum and others) and lemon thyme (Thymus citrodorus)—, all said to repel cats, with no luck. I stopped testing after Geisha died, as we no longer have a cat to use as a test subject. (My wife has developed a serious cat allergy, so Geisha was not replaced.)

How Believers Can Use Repellent Plants

If you still believe that plants have a significant repellent effect on cats and dogs, calculate their effect is limited to a distance of 6 to 8 inches (15 to 20 cm) from the plant. Therefore, the method most often recommended, that is, planting them here and there among garden plants you want to protect, is simply not going to work. Any repellent effect would be too diluted and cats would simply have to wander around the individual repellent plants to get their favorite spot.

20180418G www.gardenscentsations.com.jpg

For a repellent plant (here, Lavandula angustifolia) to be effective, you’d really need to use it as a barrier plant. Source: www.gardenscentsations.com

Other sites suggest a more likely method: using them as barrier plants, that is, surrounding the zone with dense plantings felines can’t find a way around. One site recommends using taller repellent plants as being more effective, as cats simply jump right over short ones.


Personally, the cats and dogs in my neighborhood never bother my garden, so I have no need for any kind of pet repellent. If I did, given the results of my experiments, you can be sure I’d try something other than repellent plants!

Read Keep Cats Out of Your Gardenfor a few methods that really work!20180418A big5kayakchallenge.com & domobfdi.deviantart.com

Advertisements

Common Herbs With Weedy Ways

Standard

 

20170425G confessionsofocomposter.blogspot.com.jpg

Don’t let weedy herbs run amok in your garden! Illustration: confessionsofacomposter .blogspot.com

Who doesn’t enjoy fresh herbs, those aromatic plants that add such punch to our meals? Or treat our sniffles or upset stomaches? And they’re never fresher than when we grow them ourselves. That’s why herbs are presently so popular: everyone wants to try them. And most people find them easy to grow… at first. But many herbs have a major downside: they’re moderately to highly invasive and can quickly switch from being useful plants to becoming out-and-out garden thugs.

Two Categories of Weedy Herbs

20170425C WC.jpg

Borage is an easy-to-grow annual herb… perhaps too easy to grow, as it can self-sow so abundantly that it becomes a weed. Photo: Wikimedia Commons

There are two categories of potentially weedy herbs: those that produce creeping rhizomes or stolons (or sprout from broken pieces of root) that head off in all directions, soon producing offsets that surround and overwhelm neighboring plants, and those whose invasive habits are due to self-sowing, giving hordes of babies from the seeds they drop, hordes that can quickly threaten your entire herb garden.

Here is a list of the “main culprits” along with their preferred mode of invasion:

  1. Borage (Borago officinalis): seeds
  2. Caraway (Carum carvi): seeds
  3. Catnip (Nepeta cataria): seeds
  4. Chamomile (Matricaria recutita): seeds
  5. Chervil (Cerefolium anthriscus): seeds
  6. Chives (Allium schoenoprasum): seeds

    20170425H.UserSB_Johnny, WCJPG.JPG

    Perilla or shish is a popular Chinese herb, but self-sows like the dickens. Photo: User:SB_Johnny, Wikimedia Commons

  7. Comfrey (Symphytum officinale): seeds and root sections
  8. Coriander or cilantro (Coriandrum sativum): seeds
  9. Costmary (Tanacetum balsamita): seeds
  10. Dill (Anethum graveolens): seeds
  11. Fennel (Foeniculum vulgare): seeds
  12. Feverfew (Tanacetum parthenium): seeds
  13. Garlic chives (Allium tuberosum): seeds
  14. Horseradish (Armoracia rusticana): root sections
  15. Lemon balm (Melissa officinalis): seeds
  16. Mint (Mentha spp.): stolons and creeping stems
  17. Monarde (Monarda didyma): rhizomes
  18. Mustard (Brassica nigra and B. juncea): seeds
  19. Origan (Origanum vulgare): seeds

    20170425F, Cillas, WC.jpg

    Russian tarragon (Artemisia dracunculoides) can become a garden weed. Photo: Cillas, Wikimedia Commons

  20. Russian tarragon (Artemisia dracunculus): rhizomes and seeds
  21. Shisho or perilla (Perilla frutescens): seeds
  22. Sweet cicely (Myrrhis odorata): seeds
  23. Sweet woodruff (Galium odoratum): rhizomes
  24. Tansy (Tanacetum vulgare): rhizomes and seeds
  25. Thyme (Thymus vulgaris): seeds
  26. Valerian (Valeriana officinalis): seeds

How to Control Weedy Herbs

Weedy or not, several of the herbs presented above are essential to any herb garden. Can you even imagine cooking without thyme, oregano or chives? But fortunately there are ways to grow weedy herbs while limiting their ability to invade. Here are a few:

A. Self-Sowing Herbs

20170425E Veganbaking.net, WC.jpg

Harvesting early and often prevents the plant from going to seed. Photo: Veganbaking.net, Wikimedia Commons.

  • Either remove all their flowers or harvest them before any seeds ripen;
  • Apply 3 to 4 inches (7 to 10 cm) of your choice of organic mulch (shredded leaves, wood chips, forestry mulch, etc.) throughout the herb garden, completely covering the soil. Seeds will not germinate in mulch-covered soil;
  • Hand pull when plants are still small;
  • Grow them beyond their hardiness zone. For example, fennel is hardy from zone 6 to 9 and can be weedy there if you let it go to seed. However, it won’t be invasive in zones 1 to 5.

B. Herbs With Wandering Rhizomes and Stolons

  • Cultivate them in pots on a deck, patio or balcony: that will nip any spread in the bud;

    20170425A.jpg

    Peppermint (Mentha piperita) grow inside a barrier made of sunken pots.

  • Plant them inside a barrier sunk into the ground. This could simply be a plastic pot or pail with its bottom removed. The barrier should stick up at least 2 inches (5 cm) above the ground as the rhizomes of some plants, such as mint, right will creep right over a barrier that is level with the ground.

 


Don’t hesitate to grow herbs: most are great and very productive plants and you’ll be thrilled with the results. But do take note of the invasive ones. After all, forewarned is forearmed!20170425G confessionsofocomposter.blogspot.com