Goat head or Puncture Vine (Tribulus terrestris)-Time to Get Rid of the Them

This noxious weed, an invasive species from southern Eurasia and Africa, is a menace to people, pets, livestock and bike tires. Known for their horrible spiny seeds, these pea-sized mace balls are sharp enough to puncture thin-walled tires of bikes and wheelbarrows and inflict great pain to any creature that steps on them. Hungry livestock will eat the poisonous plants when pastures are overgrazed.

2020 infestation of goat head weed next to the sidewalk along the south edge of Franklin Miles Park. The seeds will create a huge problem for dog walkers as the seeds will spread out all over the place including the sidewalk.

Even with the feeble start to our monsoon season, the rain has caused the seeds to germinate and the goat head population has gone from zero to sixty in just a few short weeks. Now is the time to get out there and weed them out. If you wait more than a few more weeks, the goat head seeds will have already started to ripen ensuring that they will be a hazard and keep coming around each summer. Seeds can live in the soil for at least 5 years, so don’t let this weed grow unchecked or you’ll have a very difficult time getting rid of it.

Goat head vine grows from a single taproot at the center of the plant. Being an annual, if you cut off the plant from the root or pull it, that will kill the plant. A 2 person team approach is very productive. One person standing cuts the plant from the root with a shovel (it only takes one well-placed slicing chop under the center of the plant) and the second person picks them up and bags them.

Some folks say they will just spray the weeds with an herbicide, but that doesn’t kill the seeds or prevent the dying plants from ripening seed before they perish. Physically removing the plants is mandatory.

To keep them from coming back, a deep layer of heavy mulch (but not straw), 2 to 3” thick will prevent the seeds from germinating and smother any small seedlings that might have been overlooked when pulling/cutting them.

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