Puncturevine
Tribulus terrestris
Washington State Classification
Class B — Control Required (Designated)
Puncturevine is a toxic plant and a serious weed in pastures, roadsides, waste places and cultivated fields.
Required control in Region 1 (all western Washington counties)
Quick Reference
Identification
Growth Habit
Puncturevine is a summer annual herb growing flat along the ground, from a simple, woody taproot. The fruit is a woody burr with sharp, rigid spines (strong enough to puncture bicycle tires or penetrate shoe soles).
Leaves
Leaves are opposite, oblong and have short stalks. They are 1 to 3 inches long, hairy, and pinnately compound (having leaflets). Each leaflet is 1/4 inch long.
Flowers
The small, yellow flowers are borne on short stalks at leaf nodes. Flowers are solitary and have 5 petals, 5 sepals and 10 stamens.
Fruit & Seeds
The fruit is a woody burr with sharp, rigid spines. Burrs break apart into 5 sections, which some say each resemble a goat's head.
Impact
Puncturevine is a toxic plant and a serious weed in pastures, roadsides, waste places and cultivated fields. The spines of the fruit can cause damage to animals and people. It's sharp spines can puncture bicycle tires and shoes. While typically not grazed, puncturevine is toxic to livestock, especially sheep, when consumed in quantity. It’s also a painful problem to the fruit pickers when growing in orchards or vineyards.
Ecology & Spread
Habitat
Puncturevine is found in pastures, roadsides, waste places, parks, agricultural areas. Please click here to see a county level distribution map of puncturevine in Washington.
Spread Mechanisms
Reproduction
Puncturevine reproduces by seed, which typically germinate from April to October, depending on conditions. Seeds commonly germinate after rainfall or irrigation. Seed production per plant typically ranges from 200 to 5,000 seeds or in some conditions up to as many as 100,000.
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Control Methods
Mechanical
- Puncturevine can be hand-pulled or controlled by hoeing or digging up, ideally prior to seed formation in the spring. If plants have already produced seeds, make sure to remove all possible spiny burrs from the ground. Make sure to wear gloves when removing puncturevine and be careful of the sharp spines. Shallow tilling, 1 inch or less, can also be used on small plants in the spring to control the plant prior to flower and seed development. Tilling deeper in the soil may just bury that will survive longer. All methods will need to be repeated as new seeds germinate during the year and for at least four years due to seed viability. Continue to monitor and control as needed. Mowing is ineffective due to the plant’s low growth form.
Cultural / Prevention
- Reduce weed establishment by maintaining a healthy planting or turf area to provide competition. Cultivation (rototilling or hoeing) will effectively eliminate plants. Reduce weed infestation by handpulling weeds. Careful digging is useful to manage weed populations. However, digging can carry undesirable weed seed to the surface and foster further germination.
Biological Control
- The puncturevine seed weevil, Microlarinus lareynii, and the puncturevine stem weevil, Microlarinus lypriformis are two biocontrol agents that have been researched and approved for the biological control of puncturevine. Unfortunately, these biocontrol agents do not provide effective control in Washington State. For more information about the biological control of puncturevine and other noxious weeds, please visit WSU Extension Integrated Weed Control Project.