The specific epithet serpens means "snake-like," and the name holds: creeping spurge moves across open ground in a low, spreading network, rooting at the nodes wherever a stem contacts soil and building dense mats that can be surprisingly difficult to pull cleanly. Native to southeastern Canada, the South Central United States, and tropical and subtropical South America, it turns up wherever ground has been opened up — sidewalk cracks, gravel paths, vegetable bed edges, and lawn margins alike. The small, rounded leaves are neat and opposite, the flowers inconspicuous white and green.

In warm climates it blooms year-round; in temperate zones it pulls back to fall. Like all annual euphorbias, it flowers young and seeds without pause, which means populations establish faster than hand-weeding can address them. Pre-emergence herbicides applied before germination are the most efficient management. The milky sap is a skin irritant, so contact is worth avoiding. Where it appears in naturalized or meadow areas it is relatively benign; in cultivated ground it needs watching from the start.