Euphorbia serpillifolia, commonly known as Thyme-Leaf Spurge, Thymeleaf Sandmat, Sand Mat, Thyme-Leaved Spurge, or Thyme-Leaved Sandmat, is an annual herb native to open, sunny habitats including grasslands, coastal dunes, and disturbed sites in a large portion of North America. It typically grows rapidly to a height of 0.1-0.3 feet (0.03-0.1 meters) and spreads 0.5-1 feet (0.2-0.3 meters), forming a low, mat-like ground cover. The plant has small, yellow, inconspicuous flowers that bloom in the summer, and its foliage resembles that of thyme, hence the common name.

Thyme-Leaf Spurge is valued for its drought tolerance and ability to thrive in poor, sandy soils, making it suitable for xeriscaping and rock gardens. It is often used as a ground cover or filler in sunny borders and can be a low-maintenance option for gardeners seeking coverage in challenging conditions. It requires full sun or part shade and prefers fast-draining sandy or loamy soils with low water needs once established. While it is not known for significant pest or disease issues, it can self-seed prolifically, which may be undesirable in some settings. Gardeners should handle the plant with care, as the sap can be irritating to the skin and toxic if ingested.CC BY-SA 4.0