Tribulus is frost tender and generally considered an annual or biennial, hardy only in USDA zone 10. It is very fast growing, self-propagated by seed, and in some regions considered an invasive weed. The yellow flowers bloom from April to August and then a week after each flower opens, it is followed by fruit development. The fruits easily fall apart into 4 or 5 hard “nutlets” or seeds, each having 2-3 sharp spines.

For medicinal use, the sun dried fruits can be used in their unprepared form, or may be dry-fried to modify their medicinal properties. Good quality Bai Ji Li fruits are hard and grayish-white.

Tribulus terrestris is native to the warm temperate and tropical regions in southern Europe, southern Asia, throughout Africa, and in northern Australia. It can thrive in very poor soil including desert regions. The Latin name tribulus originally meant “caltrop”, which is a spiky weapon, because the fruits of the plant have sharp, spiked tips.

The plant is also known by the common name “Puncture Vine” as its spikes are sharp enough to puncture a bicycle tire and to cause painful injury to bare feet. Historically, there is evidence that the seeds have been used in southern Africa as a weapon in which case murderers soaked the dried fruits in the poisonous juice of Acokanthera venenata and placed them where their victims were likely to step.