Puncturevine Tribulus terrestris

Puncturevine is an aggressive annual weed with a deep taproot native to southern Eurasia and Africa in the Zygophyllaceae family. This plant has naturalized over much of the USA. It is usually seen growing prostrate with stems spreading radially up to 3-4 feet. It grows in crop fields, pastures, along roadsides and railways, waste places, walkways, parks, yards, and other disturbed areas. It often grows where little else does in sandy or gravelly locations. 

The common name puncturevine comes from the fruit having long sharp and strong spines that can puncture feet, thin shoes, bicycle tires and the mouths of grazing animals. The common name of goathead is in reference to the shape of the fruits. The Latin name tribulus means caltrop in reference to the shape of the weapon.

The fern-like compound leaves are densely hair on hairy stems. The flowers appear during the summer and are lemon-yellow cup-shaped flowers with 5 petals. The fruit easily drops and splits into 5 hard burs with 2-5 sharp spines containing many seeds.

Puncturevine grows in full sun to partial shade and prefers a sandy soil but tolerates other soils. It is very drought tolerant and has evolved to be able to withstand drought. If left unchecked it forms dense mats and outcompetes native grasses and other plants. Grazing animal should not be allowed in an area with infestations of this plant. The plant is particularly toxic to sheep.

Control for small patches is by manually chopping the plant at ground level before flowering as it doesn't root from the stem. Pre-emergent herbicides can be applied from late winter to mid-spring. Post-emergent herbicides can also be helpful and it is best to apply to young plants.

Insects, Diseases, and Other Plant Problems: No significant problems. Weedy and invasive. Listed as invasive by the NC Invasive Plant Council.