Puncturevine
Tribulus terrestris
| Tribulus terrestris | |
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| Leaves and flower | |
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Eudicots |
| (unranked): | Rosids |
| Order: | Zygophyllales |
| Family: | Zygophyllaceae |
| Genus: | Tribulus |
| Species: | T. terrestris |
| Binomial name | |
| Tribulus terrestris L.[1] |
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| Varieties | |
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Tribulus terrestris is a flowering plant in the family Zygophyllaceae, native to warm temperate and tropical regions of the Old World in southern Europe, southern Asia, throughout Africa, and Australia.[2] It can thrive even in desert climates and poor soil. Like many weedy species, this plant has many common names, including bindii,[3] bullhead,[4] burra gokharu, caltrop,[1] cat’s head,[1][3] devil’s eyelashes,[5] devil’s thorn,[1][5] devil’s weed,[1] goathead,[1] puncturevine,[1] and tackweed.[6]
Growth
“Goathead” fruit
Thumbtack-like Tribulus terrestris nutlets are a hazard to bicycle tires.
It is a taprooted herbaceous perennial plant that grows as a summer annual in colder climates. The stems radiate from the crown to a diameter of about 10 cm to over 1 m, often branching. They are usually prostrate, forming flat patches, though they may grow more upwards in shade or among taller plants. The leaves are pinnately compound with leaflets less than 6 mm (a quarter-inch) long. The flowers are 4–10 mm wide, with five lemon-yellow petals. A week after each flower blooms, it is followed by a fruit that easily falls apart into four or five single-seeded nutlets. The nutlets or “seeds” are hard and bear two to three sharp spines, 10 mm long and 4–6 mm broad point-to-point. These nutlets strikingly resemble goats’ or bulls’ heads; the “horns” are sharp enough to puncture bicycle tires and to cause painful injury to bare feet.[7]
Etymology
The Latin name tribulus originally meant the caltrop (a spiky weapon), but in Classical times already the word meant this plant as well.[8]
Eradication
Typical habit of Tribulus terrestris
Where this is a non-indigenous species, eradication methods are often sought after. There are both biological and herbicidal solutions to the problem, but neither of them provide a solution which is both quick and long-lasting, because T. terrestris seeds remain viable for up to 3–7 years on average.
Physical
In smaller 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 preseeding time (late spring and early summer in many temperate areas). This will greatly reduce the prevalence of the weed the following year. Mowing is not an effective method of eradication, because the plant grows flat against the ground.
Another avenue of physical eradication is to crowd out the opportunistic weed by providing good competition from favorable plants. Aerating compacted sites and planting competitive desirable plants including broad-leaved grasses such as St Augustine can reduce the impact of puncture vine by reducing resources available to the weed.
