Floratam St. Augustine grass requires 6–8 hours of direct sunlight daily to thrive (UF/IFAS Extension, ENH11). With only 4 hours of filtered sun under big oaks, this site is too shady for Floratam. It will thin, weaken, and become prone to disease and weed invasion over time.
Recommendation: Switch to a shade-tolerant alternative suited for low-light conditions under trees:
- Seville St. Augustine – More shade-tolerant than Floratam (4–6 hours of filtered sun acceptable).
- Palmetto St. Augustine – Good shade tolerance, darker green, finer texture.
- Zoysia japonica (e.g., ‘Empire’ or ‘Zeon’) – Tolerates moderate shade (4–5 hours filtered sun), drought-resistant, lower maintenance.
- Or consider groundcovers like Asiatic jasmine, liriope, or native ferns if grass isn’t essential.
Important: Avoid over-fertilizing or overwatering in shade — this encourages fungal diseases (e.g., brown patch, take-all root rot). Mow higher (3.5–4”) to maximize leaf area for photosynthesis.
If the customer insists on Floratam, advise them it will likely fail within 1–2 seasons and require costly re-sodding. Better to choose the right grass for the site now.
Note: Always check local HOA or municipal rules — some restrict grass types. For tree health: avoid filling soil or sodding tightly against trunks; keep mulch ring 2–3” deep, pulled back from bark.