Quick answer: 12 native Idaho plants have a recorded bloom range that includes September.
12 species
- Black-eyed Susan Rudbeckia hirta · 42 states
- Common gaillardia (blanketflower) Gaillardia aristata · 11 states
- Common yarrow Achillea millefolium · 31 states
- Cutleaf coneflower Rudbeckia laciniata · 21 states
- Fireweed Chamerion angustifolium · 28 states
- Harebell Campanula rotundifolia · 25 states
- Pearly everlasting Anaphalis margaritacea · 18 states
- Rocky Mountain bee plant Peritoma serrulata · 22 states
- Scarlet gilia Ipomopsis aggregata · 9 states
- Scarlet globemallow Sphaeralcea coccinea · 5 states
- Shrubby cinquefoil Dasiphora fruticosa ssp. floribunda · 15 states
- Swamp milkweed Asclepias incarnata · 25 states