Centipede grass and St. Augustine grass are two common warm-season turf varieties planted across the Southern United States. Although both are aggressive growers adapted to hot climates, they are distinct species with different biological needs and characteristics. Homeowners often confuse these grasses due to their similar geographical range and use in lawns and landscapes. Understanding the differences between them is key to selecting the right turf for a specific location.
Key Differences in Appearance and Growth Habit
Centipede grass generally presents a lighter, often described as apple-green, color with a coarse texture. This turf is known for its relatively slow growth rate, relying exclusively on thick, above-ground runners called stolons to spread across the soil surface. The stolons of Centipede are notably thick and woody, which contributes to its slow establishment and overall lower density.
St. Augustine grass, in contrast, typically exhibits a deeper, blue-green color, giving the lawn a lush, highly saturated appearance. Its defining feature is the significantly broader leaf blade, which contributes to the overall coarser look and feel of the mature turf. The faster growth habit of St. Augustine leads to a much denser and more rapidly established lawn surface, often creating a thick, carpet-like canopy.
The difference in leaf width is the quickest way to distinguish the two species upon close inspection. St. Augustine blades are noticeably wider and more blunt at the tip. Centipede leaves are generally narrower and pointed, creating a difference in surface texture that is apparent to the touch. These morphological differences influence how each grass handles foot traffic and wear resistance.
Environmental Requirements and Adaptability
The primary divergence between these two grasses lies in their soil and light preferences, which determines their suitability for different landscapes. Centipede grass is uniquely adapted to thrive in acidic soils, specifically those with a pH range of 4.5 to 6.0, and it tolerates the poor, sandy conditions often found in coastal plain regions. This species has a low nutrient requirement and performs best in low-fertility conditions, often struggling when excessive fertilizer is applied.
St. Augustine grass demands a richer, more fertile soil, preferring a pH ranging between 6.0 and 7.5, which is closer to neutral or slightly alkaline. Unlike Centipede, it requires a consistent supply of nutrients and organic matter to maintain its characteristic deep color and density. When St. Augustine is grown in highly acidic soil, it is prone to iron chlorosis, a condition where the leaves turn yellow due to nutrient unavailability.
Sunlight requirements also present a major difference for homeowners selecting turf for partially shaded areas. Centipede grass requires nearly full sun exposure and exhibits poor tolerance for shade, quickly thinning out or dying back when light levels drop below six hours per day. St. Augustine grass, conversely, is recognized as having one of the highest shade tolerances among common warm-season turfgrasses, making it suitable for protected areas.
St. Augustine is the frequent choice for lawns featuring mature trees or those adjacent to tall buildings where light is filtered for much of the day. Centipede grass is slightly more tolerant of lower temperatures, often extending its viable range further north than St. Augustine varieties. This difference in light and temperature tolerance is the greatest factor influencing the successful establishment of either grass across the Southern region.
Care and Maintenance Demands
The long-term upkeep requirements for these two grasses reflect their differing environmental needs and growth habits. Centipede grass is often called the “lazy man’s grass” because it requires minimal fertilization, generally needing less than two pounds of nitrogen per 1,000 square feet annually. It also prefers a relatively low mowing height, thriving when kept between 1 and 1.5 inches, which reduces the frequency of cutting.
St. Augustine grass, due to its vigorous growth and preference for rich soil, has significantly higher maintenance demands and nutrient requirements. This turf should be mowed at a higher setting, ideally between 2.5 and 4 inches, to maintain the health of its broad blades and dense canopy. It requires more frequent applications of fertilizer and regular deep watering to sustain its deep color and aggressive growth pattern, especially during periods of drought.
Traffic tolerance is another practical consideration, particularly for highly used residential lawns. Centipede grass is notoriously poor at recovering from heavy foot traffic or compaction. St. Augustine grass handles moderate foot traffic better, recovering more quickly from wear thanks to its fast-growing nature and more robust structure.
Furthermore, St. Augustine is significantly more susceptible to serious pest issues like the chinch bug, which often requires chemical intervention, a problem less common in Centipede lawns.