Euphorbia peplus aka Petty Spurge

Euphorbia peplus, or petty spurge, belongs to the spurge family. This small annual grows across much of Europe and western Asia. Its native range also spans the Mediterranean south to Somalia. People have introduced it widely, including to the Americas. It grows in gardens, lawns, pastures, and disturbed ground. It also takes root in pavement gaps and waste ground.

Most plants stand about 0.16–0.66 feet [0.05–0.20 metres] tall. Some sources report heights of 0.98–1.64 feet [0.30–0.50 metres]. The RHS gives a spread of 0.33 feet [0.10 metres]. The plant grows fast and forms upright, branching stems. These smooth, hairless stems may turn red near the base. The thin leaves are pale green, oval, and smooth-edged. Lower leaves alternate, while leaves higher up grow in pairs. Unlike leafy spurge, this species does not spread through underground runners.

Small yellow-green flowers grow in umbels with three main rays. Triangular bracts sit beneath them and resemble small leaves. North Carolina State lists flowering from June through September. Its account also notes flowering across much of the year. Small, round capsules follow the flowers, each with three lobes. Their smooth walls enclose dark brown to black seeds. Each seed has several small pits on one side. Plants produce many seeds and spread readily into disturbed soil.

This spurge grows best in sun and soil that drains well. It also tolerates partial shade and moist ground. It accepts clay, loam, sand, and a wide pH range. Though it prefers moisture, it can withstand dry spells. The RHS rates its UK hardiness as H5. North Carolina State lists USDA zones 6–9. Plants need no pruning and have few reported pests or diseases. The RHS lists it for borders, informal gardens, and wildlife gardens. Yet it often becomes a weed, and some countries class it as invasive. Remove plants before they set seed to curb their spread.

The plant has no known food use and is harmful when eaten. All parts contain milky sap that can inflame skin. Sap in the eyes can cause lasting injury. Wear gloves when handling it, and keep children and pets away. Researchers have studied its compounds for possible cancer treatments. Growers in Australia raise it to extract these compounds. These uses do not make the raw plant safe for home treatment.