Alturas Field Office

Noxious Weeds

Tribulus terrestris L.
Caltrop family (Zygophyllaceae)

Puncturevine Tribulus terrestris L. Caltrop family

Annual with prostrate or somewhat ascending, mat forming trailing stems, each about 1/2 to 5 feet long. Leaves are pinnately compound, opposite, hairy, and divided into 4 to 8 pairs of leaflets. Flowers are yellow, with 5 petals. The fruit is hard, about 1/2 inch across, separating into five parts when mature, each with 2 to 4 sharp, hard spines resembling a goat's head. The hard spiny burs damage wool, and may be injurous to livestock as well as humans' bare feet, dogs' pads, and bike tires. Other common names include goathead, caltrop, and Mexican or Texas sandbur. Seeds can remain viable for 3 to 7 years on average.

Native to the Mediterranean, Eurasia and Africa. Grows in pastures, cultivated fields, waste areas, and disturbed sites such as roadways. Toxic to livestock in vegetative condition. It particularly thrives in sandy and sandy loam soils. In small areas, puncture vine is best controlled with manual removal using a hoe to cut the plant off at its taproot. While this is effective, removing the entire plant by gripping the taproot, stem or trunk and pulling upward to remove the taproot is far more effective. this requires monitoring the area and removing the weed throughout the pre-seeding time (late spring and early summer in many temperate areas). this will greatly reduce the prevalence of the weed the following year. Mowing in not an effective method of eradicaiton, because the plant grows flat against the ground. another avenue of physical eradicaiton is to crowd out the opportunistic weed by providing good competition from favorable plants. Chemical control is generally recommended for home control of puncture vine.

Puncturevine was first reported in California in 1903. It is likely that contaminated wool from sheep was imported from the Mediterranean region into the Midwestern United States. Today puncturevine is widespread throught the lower 48 states and parts of Canada. The worst infestations are found in Arizona, Califronia, New Mexico, Nevada, Oregon, and Texas.

Flowering Period
April to October