Field Sandbur (Long-spine Sandbur)
Cenchrus spinifex (formerly Cenchrus pauciflorus) · Warm-season, Annual (sometimes short-lived perennial), C4
Grass Family
Poaceae, Panicoideae, Tribe Paniceae
Grass Category
Invasive/Weed Grass, Pasture Weed
Variety / Cultivar
Wild type (Common Field Sandbur)
Hardiness Zones
USDA Zones 5-11. It thrives in high heat and enters dormancy/dies back after the first hard frost.
About This Grass
A light green, coarse-textured grass that grows upright or along the ground. It is most easily identified by its notorious seed heads, which are racemes of sharp, spiny burs that detach easily and cling to fur, clothing, and skin.
Blade Characteristics
Blades are 2-6mm wide (medium to coarse), flat or folded, with a pointed tip. Color is typically a pale to medium green. It has a ligule consisting of a fringe of short hairs (~1mm) and no auricles. Vernation is folded.
Root System
Shallow, fibrous root system. It does not form a dense sod but can spread rapidly and dominate areas with poor soil fertility or high sand content. Low thatch tendency.
Growing Information
Origin Region
Native to North and South America; common in sandy soils across the United States
Growth Habit
Bunch-type to spreading; can form low-growing mats via branching at the base (decumbent growth)
Sunlight & Water Needs
Full Sun (requires high light intensity); drought-tolerant once established. Prefers well-drained, sandy, or disturbed soils. Low water requirements.
Mowing & Maintenance
Maintenance is usually focused on eradication. Mowing height: 1.5-3 inches. Frequent mowing helps prevent bur formation, but burs can form even on low-growing stems. Requires low fertilization; excess nitrogen often favors desirable turf over sandbur.
Special Characteristics
Extremely low wear tolerance for sports but high survival in high-traffic sandy paths. Notable for its painful, spiny fruit (burs) which protect the seeds. Highly salt tolerant and very drought resistant.
Ecological Information
Native to the Americas but considered a noxious weed in many turf and pasture settings. Minimal wildlife value as the burs can injure animals. Often acts as a pioneer species in disturbed, sandy soils.