Hunting for the scourge of cyclists... puncturevine!

 I've written previously about puncturevine (aka goathead), Tribulus terrestris. Those "caltrop" shaped seeds are the bane of bare feet, dog paws, and bicycle tires. 

Pulling a single puncturevine plant off a sidewalk in Denver.

Puncturevine leaves and flowers.

The University of California IPM program describes the plant as follows:

Mature plant

Plants grow prostrate over open ground, but when shaded or competing with other plants they can grow nearly erect. Stems occasionally grow over 3 feet (1 m) long, have many branches, are green to reddish brown, and spread radially from the crown. Stems and leaves are covered with hairs. Leaves are mostly 2/17 to 1/5 of an inch (3–5 cm) long, finely divided into three to seven pairs of leaflets, and opposite to one another along the stem.


Flowering takes place from March through October. Flowers are bright yellow, about 1/5 to 3/5 of an inch (5–15 mm) in diameter, and are produced singly where the stem and leaf stalk meet. They open only on sunny mornings, except in shady areas.


The fruit, a woody five-lobed bur, is gray to yellowish tan, hairy, and roughly 1/5 to 2/5 of an inch (5–10 mm) in diameter. Fruits separate at maturity into five (sometimes four) wedge-shaped nutlets, each with two stout spines and several short prickles. Each nutlet usually encloses three to five seeds.

For the past week, my grandson and I have been clearing a single block in a Denver residential area of this noxious plant. We've removed at least 20 pounds, almost all from the park strip (I'm assuming I have the right to pick a plant from the city-owned park strip in front of houses). According to the Colorado Dept. of Agriculture; “Puncturevine is designated as a “List C” species on the Colorado Noxious Weed Act. It is required to be either eradicated, contained, or suppressed depending on the local jurisdictions managing this species."

I'm trying to do my part.


Now, if we can get hunters and gatherers to collect and harvest puncturevine with the same zeal  as they search for mule deer and huckleberries...


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