Goatheads Got You Down?

Puncturevine or goathead (Tribulus terrestris) is a very challenging weed that is also known as Caltrop, Tack Weed, Bull Head, Cat Head, and Mexican Sand Burr. As foreboding as these names sound, the reality is even more sinister because they are difficult to live with and challenging to kill. This is because goathead plants like to stay very low to the ground where they can escape the wrath of lawnmowers, weed-whackers, and bush-cutters, so they often get the opportunity to mature and form their terrible seed heads. What’s worse is that each plant can produce several hundred to several thousand stealthy, strong, and sharp caltrop-like burs that have the potential to seriously injure people, animals, and even thin-walled pneumatic tires (like bicycle tires). The good news (if there is any) is that they also produce small, yellow, bee-foraged flowers that serve as a subtle warning.

HOW DID IT GET THERE? 
It originated from southern Europe and northern Africa. Supposedly, it was (accidentally) imported into the United States along with livestock from the Mediterranean area. But how did it get into YOUR yard? The seeds themselves are designed for animals and people to carry them to their new homes. They attach to fur or feet and walk themselves into a new home.

WHERE DOES IT THRIVE?  
Goatheads love to take root along railways, roadsides, walkways, residential properties, cultivated fields, and other disturbed places. It thrives in hot, dry, sandy soils; but will also grow in most other soils too. The plants don’t generally survive freezing temperatures, but the seeds survive almost any condition.

HOW CAN YOU GET RID OF IT?
Long-term control of puncturevine can be achieved by reducing the number of seeds in the soil. By removing plants before they produce seeds (flowering) over several years, the plants will eventually go away. Burrs that have dropped after removal will need to be collected by sweeping the ground or patting the ground with a piece of carpet to collect the burrs. Be sure to also check places where shoes are stored and remove any burrs that may have stuck to the soles.

Puncturevine can be killed with chemicals. Always read the instructions carefully to ensure you are being safe, applying at times that won’t affect pollinators, and that you don’t accidentally kill neighboring plants.

You can also introduce your goathead plants to their natural predators: the Puncturevine Seed Weevil (Microlarinus Lareynii) and/or the  Puncture Vine Stem Weevil (Microlarinus Lypriformis). The larvae of these two species will bore into the seeds and destroy them.

WAIT… IS THERE ANYTHING GOOD ABOUT GOAT HEADS?  
Goatheads make a fantastic organic deterrent against bare-footed or bicycle-bound bandits. Just plant Puncturevine in the form of a natural barrier; or, if you happen to be on the run, simply toss a handful of goatheads in the suspected path of bandit travel and your problems should be solved in short order – unless, of course, you are dealing with boot-wearing bandits!

Best of luck keeping your head as you attempt to remove goatheads!