One of my biggest pet peeves ever is taking a nice stroll through the
neighborhood with the wife and kids and come across a section of sidewalk covered with puncturevine (Tribulus terrestris), also called goathead. I am sure most everyone has had intimate encounters with this nasty little meany. Its seed is protected by three sharp points that will easily stick into just about anything including shoes, bare feet, bicycle tires, knees and elbows, etc.Puncturevine is characterized by thin stems that radiate out from a taproot. Leaves grow out of either side of the vine and are composed of either 4-8 leaflets. Yellow flowers eventually give way to the spiny seed. Puncturevine is a summer annual, meaning it will grow through the summer but not through the winter. Each year's plants depend on the production of seed from the previous year.
As I watch my children ride through the patches on their bikes, two thoughts cross my mind. One, I'll have to patch the innertubes again because that green stuff you put into the tires just never works. Two, I hope those seeds disappear from tires and shoes before we get back to our yard. The sharp spines on the seeds serve as an effective, though painful, dispersal method. When something steps on or drives over this plant, the spines stick into the object and are then carried for a certain distance before being removed or falling off. By this means it spreads itself around.

Due to its nature, puncturevine is very easy to control. Simply do not allow the plant to reach the point where it is producing seed. A few years of prompt and early removal will result in a puncturevine free landscape. Manual removal is very effective, but herbicides also work. Whatever method you use, control as early as possible to avoid seed set. Even when sprayed it may push out seeds before it dies. All in all, it is an easy weed to control which makes me even more annoyed when I am fixing my son's bicycle innertube.