Euphorbia lathyris – Caper Spurge
Euphorbia lathyris, caper spurge, is an architectural, frost-hardy biennial from the spurge family (Euphorbiaceae), valued for its regular, blue-green habit with cross-arranged leaves. In gardens, it is surrounded by the legend of being a plant that repels moles and voles, while at the same time it is highly toxic.
Synonyms and Nomenclature
The species was described by Linnaeus (1753). The Kew POWO database lists about 10 synonyms for it; the most important include:
- Epurga lathyris (L.) Fourr.
- Euphorbia decussata Salisb.
- Euphorbion lathyrum (L.) St.-Lag.
- Galarhoeus lathyris (L.) Haw.
- Keraselma lathyris (L.) Raf.
- Tithymalus lathyris (L.) Hill
- Euphorbia spongiosa Ledeb. ex Schrank
- Euphorbia lathyris var. minor Hook. & Arn.
- Tithymalus cataputia Garsault
In English, the plant is known as “caper spurge,” “mole plant,” “gopher plant,” “gopher spurge,” and “paper spurge,” while in German it is called “Kreuzblättrige Wolfsmilch,” “Springwolfsmilch,” and “Maulwurfskraut”; the Polish name is wilczomlecz groszkowy. Note the spelling – the form “lathyrus” is incorrect.
Origin and Appearance
The natural range of the species includes Central Asia and Pakistan, but the plant has been widely introduced and naturalized in Europe, both Americas, North Africa, and Australia, where it is sometimes considered a weed. It is an erect, annual to biennial plant growing up to about 1.5 m, with a straight, frosted, blue-green stem.
The leaves are arranged in crossing pairs (decussate), lanceolate, 5–15 cm long, waxy blue-green with a light vein – this geometry gives the plant its architectural appearance. The flowers are small, greenish cyathia without showy petals, and the fruits are spherical capsules 13–17 mm in diameter, which burst open to eject seeds.
Frost Hardiness and Cultivation
Pea spurge is fully frost-resistant (USDA zones 6–9) and easily withstands winters in most of Europe. It prefers full sun and light, well-drained soil but grows almost anywhere and is very drought-resistant; it only dislikes waterlogging. Once established, it spreads abundantly by self-seeding – to limit its spread, seed pods can be removed before they mature.
Cultivation from seeds
The seeds are large and easy to handle. They are sown directly into the ground in spring or autumn – autumn sowing takes advantage of natural winter cold, which evens out germination. Some seeds only sprout the following spring. If germination is delayed, cold, moist stratification (about 3 weeks at 4°C) followed by a temperature of 15–20°C helps. Germination can be uneven, ranging from two weeks to several months.
Safety – poisonous plant
The entire plant is highly poisonous, and the milky latex strongly irritates the skin and eyes – contact can cause redness and blisters. The seeds are especially dangerous, having been mistaken for capers and causing severe poisoning. The plant is treated solely as ornamental; gloves should be worn during care, eyes protected, and it should be kept away from children and animals.
Uses and curiosities
This is an ornamental, “structural” plant for naturalistic beds, valued for its geometric, blue-green form. For centuries it was planted under the belief that root secretions repel moles and voles (hence the names “mole plant” and the German “Maulwurfskraut”), although this effect is anecdotal. In the 20th century, it was also studied as a potential latex-energy plant.
Summary
Pea spurge is a charming, frost-hardy biennial with an architectural form that renews itself by self-seeding and requires almost no care. You just need to remember its toxicity and work with gloves – in return, it provides an impressive blue-green structure in the garden and a famous reputation as the “mole plant.”
