Killing Weeds in River Rock: Glyphosate or Soil Sterilant?

Weeds in river rock around a pool can be controlled two ways:

Option 1: Glyphosate (Non-Selective, Non-Residual)

Spray over rocks; kills existing growth. No soil activity—weeds return from seed or creeping roots. Add a pre-emergent (e.g., Dimension) for 90-day seed suppression. Spot-spray every 2–3 weeks.

Option 2: Pramitol (Soil Sterilant)

One application sterilizes soil for ~1 year. Nothing roots in treated zone. Grass may creep over rocks but won't establish. Use enough water to reach soil surface, but avoid runoff into desired plants. Ideal for bordered rock walkways.

Recommendation

Pramitol is the first choice for long-term, low-maintenance control in contained rock areas.