Quick answer: 4 native plants for wet soil and rain gardens are native to Montana, 4 with a live listing as of 16 Sep 2026.
4 species
- Gray alder Alnus incana · 12 states
- Green ash Fraxinus pennsylvanica · 23 states
- Quaking aspen Populus tremuloides · 24 states
- Swamp milkweed Asclepias incarnata · 25 states