20170628A Leonora (Ellie) EnkingFlickr
Ruta graveolens ‘Jackson’s Blue’: a very blue-leaved variety. Photo: Leonora (Ellie) EnkingFlickr

These days, everyone loves traditional plants, the ones our ancestors grew. Garden writers keep dragging old plants out of mothballs and presenting them as something we should rediscover. But some of them should maybe have stayed lost in the mists of time … and that could be the case with rue.

Rue (Ruta graveolens), often called garden rue or herb-of-grace, is a plant with a long history of medicinal use and is also used as a condiment due to the acrid taste it gives to food and drinks. In addition, rue has the reputation of repelling cats and perhaps other mammals (that’s far from sure, though). This encourages gardeners interested in healing, aromatic or repellent plants to try growing it and thus rue is now fairly easy to find in many garden centers. Just look in the herb section … but planting it is maybe not such a good idea.

Of course, rue is certainly pretty enough: with its upright to mounding habit, its blue-green deeply cut leaves and its small greenish-yellow flowers, it can easily be used as an ornamental plant in a flower border. And several people automatically include the plant in the vegetable garden, hoping to keep undesirable mammals at bay.

But there are several problems with these kinds of use.

The Downsides to Rue

Rue is not your typical harmless herb, one you can just plant and enjoy. It packs quite a negative punch and you really should know about its flaws before you plant it.

Effet de la rue
A severe skin irritation due to contact with rue. Photo: Vincent, Wikipedia.

Many people find themselves suffering from skin irritation after they handle or even just brush against rue. Symptoms can include redness, a burning sensation and blisters. That’s because rue has phototoxic sap due to the furanocoumarins it releases.

Phototoxic means that irritations only appear when the skin is first exposed to the plant, then to the sun. Even if you roll around naked in rue in the evening or on a cloudy day, there’ll be no negative reaction, nor will there be if you wash your skin with soapy water after contact. But going to pick vegetables on a sunny day in a garden with a rue border has sent some people to the hospital! Children are generally more sensitive to furanocoumarins than adults and should never be allowed to touch this plant.

Always wear gloves when handling rue!

Rue is also poisonous. This can seem surprising, given that this plant has a long although limited use in Mediterranean cuisine, but it’s the dose that makes the poison. A single chopped rue leaf added to a salad is not likely to be harmful, but eating too much will cause gastric distress and has sometimes led to death.

As for its medicinal uses, and there were many (it was supposed to keep away the plague, for example), most have fallen by the wayside over time and are no longer considered viable. Even back when rue was a major medicinal plant, it was never so much a curative as an abortive. Legend has it that Julia Titi, the daughter of the Roman emperor Titus, died after consuming it during a forced abortion.

Although rue is no longer used in modern medicine, some herbalists still claim a host of uses for it. If someone recommends it to you, think twice!

Also, rue stinks. And that’s probably best, because its pestilential odor paired with its pungent taste dissuades humans (and animals) from consuming it in excessively large quantities.

Its reputation as an animal repellent (people regularly claim it will keep everything from birds to beavers out of the garden) is certainly exaggerated. A few mammals (some cats, for example, but not all) will avoid brushing against it, probably because of its smell, and very few will eat it, but that won’t stop them from just squeezing past. It loses any effectiveness at only 6 to 10 inches (15 to 30 cm) from the plant. To use it to keep animals out of your garden, you’d have to plant in a border all around the garden … and cross your fingers that the unwanted animal simply didn’t jump right over it. (The plant rarely reaches more than 27 inches/70 cm high in cold regions, up to 3 feet/1 m in milder zones.)

Then there is its invasiveness to consider. Originally native to the Mediterranean region, rue has escaped from cultivation in North America, South America and Australia and is considered a noxious weed in many areas. Is that what you really want for your garden?

If You Still Want to Grow Rue

20170628D Kurt Stüber, WC
Rue (Ruta graveolens). Photo: Pixabay

In spite of all its disadvantages, there many people who will still want to grow rue, sometimes because its use is traditional in their culture or because of their belief in herbal remedies. And it’s attractive to beneficial insects too, including pollinators. (However, so are many plants that attract beneficial insects, yet aren’t poisonous and invasive.)

If you have the right conditions, rue is not at all difficult to grow. It needs full sun and a well drained to dry soil that is neither too rich or too acid and it does fine in alkaline soils. It’s a short-lived perennial (4 or 5 years) that maintains itself by self-sowing. It’s fairly hardy, up to zone 5, although a bit of winter protection could be useful. In colder areas, you can grow it as an annual.

Rue: now that you know more about it, you can decide whether you want to grow it!

Larry Hodgson is one of Canada’s best-known garden communicators. He has notably been editor-in-chief of HousePlant Magazine, Fleurs, Plantes et Jardins, À Fleur de Pot and Houseplant Forum magazines and is currently the garden correspondent for Le Soleil and radio garden commentator for CKIA-FM Radio. He has written for many garden publications in both the United States and Canada, including Canadian Gardening, Harrowsmith, Horticulture, Fine Gardening and Organic Gardening. He also speaks frequently to horticultural groups throughout Canada and the U.S. His book credits include The Garden Lover’s Guide to Canada, Complete Guide to Houseplants, Making the Most of Shade, Perennials for Every Purpose, Annuals for Every Purpose, and Houseplants for Dummies, as well as nearly 60 other titles in English and French. He is a past president of the Garden Writers Association (now Garden Communicators International) and the winner of the prestigious 2006 Garden Media Promoter Award offered by the Perennial Plant Association. He resides in Quebec City, Quebec, Canada.

6 comments on “Rue: the Herb that Shouldn’t Be

  1. Pingback: Can Plants Really Repel Cats and Dogs? – Laidback Gardener

  2. Roberta Irvine

    Thank you for this article. I get poison ivy every year when I do my spring garden clean up. I was looking for a round leafed plant, I didn’t realize it could have different forms!

  3. Fay Cotton

    enjoyed this article while scratching my hands after weeding near Rue 2 days ago. I planted it specifically for 1 species of butterfly: the Giant Swallowtail (Grande Porte-queue). rarely sighted in Quebec. Because I also planted Prickly Ash, the only native tree in the lemon family in Quebec, and a preferred host to this caterpillar, I now get a Giant Swallowtail or 2 each year. But I learned my lesson! Rue, and American cow parsnip (Berce Laineuse)! The black swallowtail (papillon du céleri) also chose Rue early this year to lay eggs on and i see them often now. They like to feed on the nectar of heavenly smelling Hesperis matronalis. but I digress…. thank you for this article! now I can pat my cat again, knowing it wasn’t her that gave me poison ivy.

    • And do put on gloves next time you touch the rue!

      • I have had rue in my garden for years and rarely experienced a skin reaction. Occasionally would have very minor rash on arms, but didn’t know what caused it because I garden for other people, also. This summer I got lazy on a very warm day and didn’t change into my long sleeve shirt and pants for work at my own garden. Cutting back my rue has caused the most miserable, itchy and painful welts all over my arms and legs. Over-the-counter products have produced no relief. I am seeing my doctor tomorrow to get a prescription for a steroid. BEWARE of this plant. So thankful I at least was wearing gloves!

      • Thanks for reinforcing the warning!

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