Garden Myths Gardening Harmful animals Weeds

Garden Myth: Does the Mole Plant Really Repel Moles?

Illustration of mole doubtfully examining a mole plant.

By Larry Hodgson

There are quite a few websites that recommend planting a biennial (occasionally annual) spurge known as the mole plant or gopher plant (Euphorbia lathyris)* to repel moles and gophers from the garden. The claim is either that it gives off an odor that moles and gophers simply cannot stand or its poisonous roots will keep them away. But that turns out to be false. Neither pest seems to be even slightly bothered by the plant’s presence. So why waste your time? 

*Among its other common names are caper bush, caper spurge, gopher spurge, mole plant, mole weed, myrtle spurge, spring wort, spurge, virgin’s milk and wild caper.

But worse yet, this plant, originally from the Mediterranean region, self-sows abundantly in many situations and has become a noxious weed in many places on five continents. Growing it is even banned in New Zealand and parts of Australia. 

And it’s also poisonous. The white sap that flows abundantly from the slightest wound is toxic not only if consumed, but even to the touch, causing skin irritation, even temporary blindness if it reaches the eye. People have been hospitalized after mistakenly eating it (the seeds can look like capers). It is also toxic to pets and farm animals, although goats are said to be able to eat it (it does render their milk toxic, though). 

Mole plant in leaf.
The mole plant is not unattractive. Photo: JH Mora, Wikimedia Commons

The mole plant is also sold by some seed catalogs as an ornamental and there is no denying it can be attractive, with its stiffly upright purplish to blue-green stems 3 to 5 feet (90 to 150 cm) tall and long, lance-shaped leaves with a white central vein set in pairs that form a perfect cross when seen from above. 

A mole plant in bloom. Photo: Syrio, Wikimedia Commons

The bright chartreuse yellow flowers in late spring or early summer are striking and the round seed capsules that follow are not unattractive either… although, if you don’t want this plant to spread, you should clip them off. 

Another plus, it remains resolutely green during the worst of droughts, when everything else is brown. 

However, given its toxicity and risk of escaping from culture to become a weed (it’s especially invasive in fairly arid climates in USDA hardiness zones 5 to 9), not to mention that it will not repel “varmints” as promised, I think this is a plant it is best to avoid.

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.

3 comments on “Garden Myth: Does the Mole Plant Really Repel Moles?

  1. Are there similar euphorbias that don’t try to take over the garden? I like euphorbia polychroma, but I’d like something taller.

  2. You have to be very careful with perennial euphorbias. Most are invasive… and then there are quite a few that aren’t going to be hardy enough, E. polychroma being an exception on both levels. Maybe you could grow E. colorata or E. myrsinites. You see various sources with different hardiness ratings, but they do all right in my zone 4 climate with abundant snow cover. You also might need snow cover for them to survive. Invasive ones include E. cyparissias and its cultivars and E. griffithii and its cultivars.

  3. Thank you for mentioning this. I still see it available in nurseries, and people actually purchase it singly, as if a single plant will repel gophers from their gardens. I dislike it both because it is an annoying weed, and also because it does nothing to repel gophers. Technically, gophers and perhaps moles will avoid the larger roots, since the roots exude caustic sap. However, a garden must be surrounded by such roots to effectively repel gophers. So much vegetation would limit space for the rest of the garden, and would not prevent gophers and moles from simply going around or under, or even over the surface of the soil if they want to.

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