Euphorbia maculata aka Spotted Spurge

Euphorbia maculata, or spotted spurge, belongs to the spurge family. It grows as a summer annual and dies after frost. Its native range includes southeastern Canada and much of the central and eastern United States. It extends south to Belize and includes Cuba and the Bahamas. People have introduced it to many other regions. It grows in gardens, roadside ground, gravel, and pavement cracks.

This fast-growing weed forms a low, broad mat. Plants stand about 0.02–0.33 feet [0.006–0.10 metres] tall. They can spread to 3 feet [0.91 metres] wide. Thin, hairy stems lie along the ground. Each stem seldom exceeds 1.5 feet [0.46 metres] long. Bright sun can turn them pale red. A thick taproot may reach 2 feet [0.61 metres] deep. The stems rarely form roots where leaves join them.

Small, simple leaves grow in opposite pairs along each stem. They are round to oblong and dark green. Some have a red tint and a dark central blotch. Fine hairs cover the leaves, with more beneath. Some leaf edges have small teeth. Broken stems release a white, milky sap. Small flower cups form where leaves meet the stems. Their greenish-white edges may show pink or white. Male and female flowers sit inside each cup. Flowers appear from summer into early fall. Bees and wasps pollinate them. The fruit is a tiny, hairy capsule with three lobes. Birds, including doves, quail, and sparrows, eat the seeds.

Spotted spurge favors full sun and soil that drains well. It grows in sandy or gravelly ground and tolerates poor soil. Regular water suits it, though it also withstands drought. The source lists USDA zones 5–9, but frost kills the plants. It needs no high humidity. Even small seedlings can flower and produce many seeds. Wet seeds cling to fur, shoes, and mower tires. This helps the weed spread through beds and plant nurseries. Its low stems escape mowing. Removing plants before seed forms helps limit its spread. The source does not recommend it for most gardens. It reports no known disease or insect problems.

All parts contain latex that can harm people and pets. Eating the plant can cause blisters inside the mouth. Sap can irritate skin or cause a severe rash. Eye contact can damage the cornea, sometimes for good. Wear gloves when handling it, and keep children and pets away. Researchers are studying its sap for possible skin cancer treatment. That research does not establish a safe home remedy.