The Mission of the Yellowstone County Weed Department is to assist the public, private, and other government agencies to manage and control existing noxious weed infestations as well as to prevent new invasive species from infesting Yellowstone County.

PuncturevineTribulus terrestris L.

Caltrop family - Zygophyllaceae

Photo from Weeds of the West, revised edition

Attribute	Information
Growth Habit	Annual, mat forming, trailing stems to 5 feet long.
Leaves	Opposite, hairy, divided into 4-8 pairs of leaflets. Oval leaflets 1/4 to 1/2 inch long.
Stem	Prostrate, trailing, hairy, many branched from root crown.
Flower	5 petals, yellow, in leaf axils, to 1/2 inch wide.
Roots	Fibrous.
Seeds	Fruit break into 5 sections with 2-4 seeds per capsule. Capsules tack like structures with 2 sharp spined, resembling the head of a goat.
Reproduction	Seeds.
Habitat	Croplands, pastures, along transportation rights-of-way and in urban areas.
Biological Controls	Puncturevine seed weevil (Microlarinus lareynii), Puncturevine stem weevil (Microlarinus lypriformis).
Herbicides	Roundup Ultramax, Plateau, Telar XP, E2, Oust XP and Method.