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Euphorbia lathyris

caper spurge

Euphorbiaceae

Eastern Mediterranean and southwest Asia

Attracts Pollinators Deer Resistant Drought Tolerant

SunFull Sun – Part Shade

WaterLow · drought-tolerant

HardinessZones 6–9

Overview

Euphorbia lathyris is an erect biennial in the spurge family, growing 60-150 cm (24-59 in) tall on a stout, blue-green stem that branches near the top. The narrow, lance-shaped leaves are 5-20 cm (2-8 in) long, blue-green with a pale midrib, and held in four neat ranks of opposite, crosswise pairs. In its second year it produces a flat-topped head of small greenish cyathia, the cup-like flower structures typical of spurges, each with crescent-shaped nectar glands. These ripen into rounded three-lobed capsules about 1-2 cm (0.4-0.8 in) wide that loosely resemble large capers but are toxic. The whole plant exudes an acrid milky latex when cut. It grows on disturbed, cultivated, and waste ground on free-draining soils in sun or light shade. All parts are toxic if eaten, and the latex irritates skin and eyes on contact. After flowering and seeding in the second year the plant dies, relying on seed to continue.

Native Range

Euphorbia lathyris is thought to be native to the eastern Mediterranean and southwest Asia, though its long history of cultivation obscures its original range. It has naturalised widely across Europe, North America, and other temperate regions as a plant of disturbed ground. It grows on cultivated and waste soils from lowlands to low hills.

Suggested Uses

Euphorbia lathyris is grown occasionally in dry borders and gravel gardens for its upright blue-green form and ranked foliage. It has a folk reputation as a mole deterrent, though evidence for this is limited. Its toxicity and free self-seeding limit its use where children, pets, or livestock are present.

How to Identify

Identify it by the tall, blue-green, sparingly branched stem and narrow leaves held in four straight ranks of opposite, crosswise pairs. The flat head of small green cup-shaped flowers and the rounded, three-lobed caper-like capsules set it apart from similar plants. Any cut releases a milky white latex, confirming a spurge.

Appearance

Size & Dimensions

Height2' - 4'11"

Width/Spread1' - 1'6"

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~6 weeks

Summer

Small greenish cyathia open in flat-topped clusters from June to July in the plant second year. They are wind- and insect-pollinated and lack showy petals. Three-lobed capsules ripen through late summer and split to fling seed a short distance.

Detailed Descriptions

Foliage Description

blue-green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 5-12 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.0 - 7.5(Neutral)

357912

Soil Types

loam sand rocky

Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

hardy

Time to Maturity

2 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Grow in full sun to light shade on free-draining soil of moderate fertility; it tolerates poor and stony ground. As a biennial it forms a leafy rosette and stem in the first year and flowers, seeds, and dies in the second. It withstands frost across cool temperate zones and needs little watering once established. Rich, wet soils give soft growth and shorten its life. It self-seeds freely, so volunteer plants often appear nearby. The milky latex irritates skin and eyes, and all parts are toxic if swallowed.

Pruning

Spent flowering stems can be cut down after seeding to limit self-sowing, as seed scatters when the capsules burst. The cut stems release an irritant latex that can affect skin and eyes. Whole plants are removed once they die after their second year.