[3][4][5][6] It is adapted to dry habitat, but only on upper floodplain fringes, or adjoining depressions containing vernal pools or similar structures.

Ambrosia pumila is a hairy perennial herb not exceeding 0.5 metres (1.6 ft) in height.

The pistillate heads each yield usually one fruit, which is a fuzzy burr only a few millimeters wide with short, soft spines.

Critical habitat was declared for the species in 2010, listing areas that should be protected for the survival of the plant.

[7] Protected areas containing this plant include sections of land in the cities of Temecula and Oceanside, near Fallbrook and Lake Hodges, and within the bounds of Mission Trails Regional Park and the San Diego National Wildlife Refuge.