Spurge (Euphorbia spp). Sappy succulents, annuals or perennials that like hot, dry weather.
Common names: Ground spurge, prostrate sandmat, prostrate spurge, spotted spurge
Range: Native to all of the contiguous US and into Canada and Mexico.
Control: Spot spraying vinegar-based organic herbicides.
The Euphorbiaceae family is large and within it, Spurge is a prolific weed with many species that are frequently confused with each other. In older plant identification manuals the genus name often appears as Chamaesyce, though today the spurge genus is generally called Euphorbia. And while there are many attractive plants in this family, such as the seasonally popular poinsettia, the prostrate weed with a deep central tap that grows in sunny areas in the yard, garden, and potted plants, is not one of them.
Spurge with sprigs of purslane (photo by Maggie Dwyer)
USDA map for distribution of Euphorbia maculata, also called Chamaesyce maculata
Some insight about spurge from the University of Arkansas Division of Agriculture, Research and Extension:
The Latin name Chamaesyce translates as “low growing on the ground” and is an apt name for the spurges in general and this species in particular. It is an old name used in Gerard’s 1633 edition of The Herbal. Botanists have traditionally combined all white latex producing plants into the large Euphorbia genus but in recent years the trend has been to separate the spurges out into their own group.