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Puncture Vine (Tribulus terrestris)

Description: Puncture vine, also known as caltrop, ground burnut, goat’s head, or tackweed, is an annual reproducing by seed. It has a taproot from which the several stems are branching, hairy, wide spreading, and 1 to 5 feet long. The leaves are opposite, dark green, about 2 inches long, and pinnately divided into 5 to 7 pairs of leaflets. The leaflets are ½ inch long, narrowly ovate, and hairy. The flowers are on short stems arising in the axils of the leaves. Each has 5 pale yellow petals that mature into a flat, dry seedpod about ½ inch wide. The seedpod breaks into 5 parts at maturity. Each section has 2 sharp spines. The plant blooms from July to September and matures from August to October.

Distribution: Puncture vine is found infrequently growing in sandy soils throughout Iowa. It prefers waste ground, parking areas, playgrounds, railroads, and roadsides. It may be poisonous to animals. Seeds can remain viable in the soil for many years, so disturbances can provide areas for germination and plant growth.

What’s The Problem?: Sharp spines can puncture bicycle or vehicle tires. The plant can be toxic to livestock, especially sheep. Puncturevine can also impair recreational opportunities by making a trip into infested areas very painful from the sharp spines poking into skin, leather, etc.

Management Methods: Although generally not a major pest in Johnson County, puncture vine can become a nuisance in certain areas. The spines can be particularly hard on bicycle tires. Puncture vine can be controlled by pulling plants out of moist soil, but be sure to wear gloves to avoid spines. Good grassland management and prescribed burning may help to control or reduce infestations. Herbicides can also provide effective control if they’re applied when the plants are young and small. If herbicides are used, be sure the product chosen is labeled for control of puncture vine, and, as with any pesticide, read and follow label directions closely.

 photo of Puncturevine

photo of Puncturevine

Photo couresy of Weeds of Nebraska and the Great Plains published by Nebraska Department of Agriculture

photo of Puncturevine

Photo courtesy of Washington State Noxious Weed Control Board