Quick answer: 24 native Louisiana plants have a recorded bloom range that includes September.
24 species
- Big bluestem Andropogon gerardii · 25 states
- Black-eyed Susan Rudbeckia hirta · 42 states
- Blue mistflower Conoclinium coelestinum · 26 states
- Butterflyweed Asclepias tuberosa · 37 states
- Cardinal flower Lobelia cardinalis · 37 states
- Carolina jessamine Gelsemium sempervirens · 9 states
- Common yarrow Achillea millefolium · 31 states
- Devil's walking stick Aralia spinosa · 14 states
- Eastern purple coneflower Echinacea purpurea · 22 states
- Great blue lobelia Lobelia siphilitica · 32 states
- Hollow Joe-pye weed Eutrochium fistulosum · 14 states
- Inland sea oats Chasmanthium latifolium · 3 states
- Loblolly bay Gordonia lasianthus · 5 states
- Mexican hat Ratibida columnifera · 17 states
- Pink-scale blazing star Liatris elegans · 5 states
- Prairie blazing star Liatris pycnostachya · 16 states
- Scarlet rosemallow Hibiscus coccineus · 5 states
- Sideoats grama Bouteloua curtipendula · 25 states
- Stokes aster Stokesia laevis · 4 states
- Swamp sunflower Helianthus angustifolius · 15 states
- Switchgrass Panicum virgatum · 24 states
- Trumpet vine Campsis radicans · 24 states
- Virginia saltmarsh mallow Kosteletzkya pentacarpos · 4 states
- Witch-hazel Hamamelis virginiana · 28 states