Turf
St. Augustine grass
Stenotaphrum secundatum · Poaceae
Also called: St. Augustinegrass, Buffalo grass (Australia/South Africa usage), Palmetto St. Augustine (cultivar)
St. Augustine grass (Stenotaphrum secundatum) is a high-water turf well suited to Tucson and the low desert. It thrives in part shade to full sun. Expect inconspicuous blooms summer.
St. Augustine grass at a glance
- Water use
- High (established)
- Sun
- Part shade to full sun (the most shade-tolerant warm-season turf; performs with 4-5 hours of sun)
- Mature size
- Turf height 2.5-4 in mowed; spreads by runners
- Growth rate
- Fast (spreads by above-ground stolons)
- Bloom
- Inconspicuous, Summer (inconspicuous seedheads; mostly sterile, spreads vegetatively)
- Cold hardiness
- Least cold-hardy common turf; browns and can be damaged below ~28-32 F, dormant in winter, and sensitive to hard Tucson frosts. Heat-tolerant but needs ample water.
- Soil
- Prefers fertile, well-drained soil; tolerates some salinity but is more demanding than bermuda and dislikes compacted, low-fertility desert soil without amendment.
- Native range
- Coastal Gulf of Mexico, Caribbean, and warm parts of the Americas and Africa.
- Best used as
- Lawns in shaded yards / under trees where bermuda fails, General turf
- Wildlife
- Minimal; functional turf.
- Toxicity
- Non-toxic; lower pollen than bermuda (largely sterile).
How to grow St. Augustine grass in Tucson & the low desert
Watering
Warm-season grass with the highest water demand of common desert turfs: water deeply and frequently in summer, roughly 1.5-2.5 in/week, more in extreme heat; it wilts quickly when dry. Reduce in winter as growth slows but it stays semi-green longer than bermuda.
Fertilizer & nutrients
Feed during active growth (spring through early fall) with nitrogen about every 6-8 weeks (0.5-1 lb N per 1,000 sq ft); apply iron for color in alkaline desert soil, where it is prone to chlorosis.
Pruning & care
Mow high at 2.5-4 in with a rotary mower (its coarse, stoloniferous growth dislikes low mowing); avoid scalping. Dethatch as needed since it builds thatch readily.
Notes
Established only from sod or plugs (no practical seed). Its main niche in Tucson is shaded lawns under trees or on the north side of structures, where bermuda thins out. Trade-offs: noticeably higher water use, frost sensitivity, susceptibility to chinch bugs and iron chlorosis, and thatch buildup. AMWUA notes any lawn is high-water and recommends removing non-functional turf.
Sources: University of Arizona Cooperative Extension (Turfgrass publications); AMWUA; Tucson.com / Pima County Master Gardeners; Arizona sod growers (West Coast Turf, Evergreen Turf)