Goatheads are a tough adversary. Depending on weather conditions, from the time it first sprouts, a goathead vine can begin forming flowers and then thorns within 15 to 25 days.
Left unchecked the plant continues to grow to over ten feet in diameter and can drop hundreds of goathead thorns during the growing season.
Each goathead has five thorns which holds two to four seeds. The thorns are capable of puncturing bicycle tires, sticking in shoes or dog paws. The seeds can survive 5+ years in the ground before sprouting.
Goatheads which are also called Puncturevine (Tribulus Terrestris), are an invasive noxious weed that originated in Eurasia. The typical growing season in the Wenatchee area is June through October. The plant grows more actively in higher heat (July/August), after rain storms and in disturbed soil.