Sandburs are annual grasses that form seeds with sharp spines, making them a troublesome weed. While adapted to dry, sandy soils, sandburs grow in other soils as well. Their burs are painful and attach readily to clothing and animal fur, spreading the weed.
The most effective means of preventing sandburs is by keeping lawns healthy. According to the Texas A&M AgriLife Extension Service, it is important for homeowners to water, fertilize and mow to maintain a thick, lush turf, which is resistant to weeds of any type. Pre-emergent herbicides mixed with fertilizers are effective if applied two to four weeks before the seeds germinate. It is essential that the owner apply these chemicals per the label directions, as over-application damages the turf grass, giving more opportunity for additional weeds to form. Post-emergent herbicides help in controlling young weed sprouts; however, more mature plants are difficult to kill and often leave seeds to start new weeds the next year. In areas where there are many weeds, the owner should consider reseeding spots where killing the unwanted sandburs results in bare spots.
Laysan Island of the Pacific Ocean illustrates the invasive nature of sandburs. Once home to many rare plants and animals, sandburs, introduced by troop movement during World War II, are responsible for crowding out many native bunchgrasses. The destruction of their native habitat by the weeds, along with the introduction of non-native rats, is responsible for the loss of several species of local birds.