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Field guide
Goathead (Tribulus terrestris)
Juan Carlos Fonseca Mata · CC BY-SA 4.0

also Puncturevine

Goathead

Tribulus terrestris

Family:
Zygophyllaceae
Elevation:
1,000 ft – 6,500 ft
Bloom:
Apr – Oct
Region:
Southwest

Non-native invasive. This plant spreads aggressively and displaces native flora — it's here so you can recognize and manage it, not plant it. See Common problems & fixes below for removal guidance.

A ground-hugging annual that spreads flat mats of trailing stems with paired, ferny leaves and small yellow flowers. This non-native invasive is notorious for the hard, sharp-horned burrs it drops — spiny seed cases that puncture bike tires, injure bare feet and pet paws, and hitchhike everywhere.

Care · tuned to the Southwest

Water

Thrives on hot, dry, disturbed ground, using a deep taproot to survive drought while sprawling across bare soil; it does best exactly where other plants are sparse.

Sun & exposure

Full sun on hot, open, bare ground.

Soil

Invades compacted, disturbed, poor soils along sidewalks, driveways, trails, vacant lots, and cracks in pavement.

In the Southwest

Harmful because its woody spined burrs injure people, pets, and livestock, puncture tires, and spread by clinging to feet and tires; each plant makes many long-lived seeds. Invasive — remove, never tolerate.

Common problems & fixes

  • Spiny burrs injure paws and bare feet, puncture bike tires, and cling to shoes to spread

    Fix — Pull the whole mat by the taproot before flowers turn to burrs; rake and sweep up dropped burrs (a carpet drag lifts them) and bag them.

  • Each plant sets many hard, long-lived seeds that build a persistent seed bank

    Fix — Hoe or hand-pull young plants repeatedly through the warm season before they seed; apply a pre-emergent in spring on chronic sites.

  • Reestablishes quickly on bare, compacted paths and lots

    Fix — Remove plants early, mulch or plant competitive groundcover, and consider puncturevine weevils for large infestations.

Pets & toxicity

The rigid spiny burrs injure paws and can lodge in a pet's pads, mouth, or gums, causing pain and infection; the foliage can also cause photosensitization and nitrate poisoning in grazing livestock.

Easy to confuse with

  • Spotted spurge (Euphorbia maculata) — milky sap and no spiny burrs
  • Arizona poppy (Kallstroemia) — larger showy orange-yellow flowers and non-puncturing fruit

Sources

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