Prostrate Spurge Euphorbia maculata

Spotted spurge is a summer annual weed with a prostrate growth habit that flourishes in warm climates and dies after frost. It is typically found in sidewalk cracks, gravel, roadsides, gardens, and sometimes woodlands. It is native to Southeastern Canada, the Central and Eastern United States, and as far south as Bolivia and Belize. It is a member of the spurge family (Euphorbiaceae). The specific epithet, maculata, is Latin and means "spotted" or 'blotched." Each leaf has a small maroon to purple spot in the center; hence, the specific epithet and the common name, spotted spurge. It was initially described in 1753 by Carl Linnaeus.

This weed likes full sun, regular watering, and well-drained, sandy, or gravelly soil. It will thrive in moderate temperatures and does not require high humidity. Spotted spurge can germinate when temperatures are as low as 60 degrees and as high as 100 degrees Fahrenheit. It tolerates poor soils and drought. Because spurges flower when young and have little or no seed dormancy, weed populations can increase rapidly. Remove plants as quickly as possible to reduce seed production; though they can be time-consuming to hand weed due to the number of seedlings that form. Mowing is ineffective because plants grow so close to the ground. Spurges are well-managed by most preemergence herbicides labeled for use.

Spotted spurge is mat-forming, 0.25 to 4 inches tall, and spreads up to 3 feet. The small, oblong leaves grow opposite on the stem and have an irregular maroon-to-purple spot in the center. When stems are broken or injured they emit a milky white sap similar to dandelion. The plant forms a thick taproot, which can extend two feet into the soil and rarely or never roots at the leaf nodes. The small greenish-white flowers appear in summer and early fall. Even tiny seedlings can flower and set prolific amounts of seed with limited or no dormancy. It is not recommended as a cultivated plant for most gardens.

Spotted spurge is similar to Euphorbia prostrata and  known by the common name, prostrate spurge. They can be easily distinguished from each other because Euphorbia prostrata has shorter leaves that are more rounded at the tips and there is no spot in the center.

Diseases, Insects, and Other Plant Problems:  There are no known diseases or insect problems. This plant spreads aggressively. Spurges are some of the most common warm-season weeds in container nurseries, agriculture, and landscape ornamental beds.The seeds easily attach to animal fur, to our shoes, and to the tires of lawn mowers. They remain dormant over the winter months then germinate to produce new plants for the summer months.

This plant is considered toxic to humans and pets.The sap of the spotted spurge can cause skin irritation or a rash. Protective gloves should be worn when handling this weed. Keep out of the reach of small children and pets.

VIDEO Created by Laura Barth for "Houseplants, Succulents, and Cacti," a plant identification course offered in partnership with Longwood Gardens.

More information on Euphorbia.