I had asked this question a couple of years ago. Now I can safely say that this hibiscus tolerates substantial salt. We live on a saltwater bayou. Planted two mature plants about three years ago. Since then they have repeatedly been submerged by high tides/hurricanes, and keep on coming. More conclusively, we saved seeds 12 months ago, and planted them , after 6 months in a dry land pot, in the same marshy, salt water bayou area - they are doing great!