[3][4] Ambrosia ilicifolia is a small, matted shrub under 1 metre (3.3 ft) in height.

Its stiff, straight branches are green, glandular, and leafy when young, and light gray and leafless when older.

The holly-like leaves are leathery but brittle, oval-shaped to rounded, and edged with spine-tipped teeth.

Each pistillate head produces usually two fruits, which are yellow-brown burrs nearly 2 centimeters wide.

Each burr is rounded, sticky, and covered in hooked spines.