• Flood-and-drought whiplash on the Mississippi system is the dominant climate signal here — wet-cycle floods overtop levees while dry-cycle drawdowns stress bottomland hardwoods that depend on periodic but bounded inundation.
• Sea-level rise propagates upstream as saltwater wedge intrusion in the lower delta; bald cypress and water tupelo decline in increasingly brackish zones.
• Garden-relevant: bottomland natives (bald cypress, oakleaf hydrangea, swamp white oak, southern crabapple) are well-suited to lower-Mississippi gardens but require honest water-table siting; high-and-dry placement breaks the design.