Quick answer: 78 native Illinois plants have a recorded bloom range that includes September.
78 species
- Big bluestem Andropogon gerardii · 41 states
- Black-eyed Susan Rudbeckia hirta · 44 states
- Blue grama Bouteloua gracilis · 19 states
- Blue mistflower Conoclinium coelestinum · 32 states
- Blue vervain Verbena hastata · 34 states
- Brown-eyed Susan Rudbeckia triloba · 21 states
- Buffalograss Bouteloua dactyloides · 19 states
- Bunchberry Cornus canadensis · 18 states
- Butterflyweed Asclepias tuberosa · 40 states
- Canadian burnet Sanguisorba canadensis · 20 states
- Cardinal flower Lobelia cardinalis · 41 states
- Closed bottle gentian Gentiana andrewsii · 23 states
- Common buttonbush Cephalanthus occidentalis · 29 states
- Common evening primrose Oenothera biennis · 30 states
- Common selfheal Prunella vulgaris · 25 states
- Common sneezeweed Helenium autumnale · 40 states
- Common yarrow Achillea millefolium · 47 states
- Compass plant Silphium laciniatum · 20 states
- Crimson-eyed rose-mallow Hibiscus moscheutos · 28 states
- Culver's root Veronicastrum virginicum · 32 states
- Cup plant Silphium perfoliatum · 27 states
- Cutleaf coneflower Rudbeckia laciniata · 43 states
- Dense blazing star Liatris spicata · 24 states
- Devil's walking stick Aralia spinosa · 21 states
- Dotted blazing star Liatris punctata · 17 states
- Eastern purple coneflower Echinacea purpurea · 24 states
- Fall obedient plant Physostegia virginiana · 37 states
- Fewleaf sunflower Helianthus occidentalis · 16 states
- Fireweed Chamerion angustifolium · 37 states
- Flowering spurge Euphorbia corollata · 29 states
- Grayhead coneflower Ratibida pinnata · 26 states
- Great blue lobelia Lobelia siphilitica · 36 states
- Groundnut Apios americana · 21 states
- Harebell Campanula rotundifolia · 35 states
- Hollow Joe-pye weed Eutrochium fistulosum · 24 states
- Indiangrass Sorghastrum nutans · 37 states
- Inland sea oats Chasmanthium latifolium · 21 states
- Jerusalem artichoke Helianthus tuberosus · 26 states
- Little bluestem Schizachyrium scoparium · 42 states
- Maypop passionflower Passiflora incarnata · 21 states
- Mexican hat Ratibida columnifera · 17 states
- New England aster Symphyotrichum novae-angliae · 29 states
- Orange coneflower Rudbeckia fulgida · 23 states
- Partridge pea Chamaecrista fasciculata · 30 states
- Partridgeberry Mitchella repens · 31 states
- Pearly everlasting Anaphalis margaritacea · 38 states
- Prairie blazing star Liatris pycnostachya · 19 states
- Prairie ironweed Vernonia fasciculata · 14 states
- Purple prairie clover Dalea purpurea · 18 states
- Rocky Mountain bee plant Peritoma serrulata · 26 states
- Roundhead lespedeza Lespedeza capitata · 30 states
- Scaly blazing star Liatris squarrosa · 22 states
- Scarlet beebalm Monarda didyma · 25 states
- Sensitive fern Onoclea sensibilis · 26 states
- Showy goldenrod Solidago speciosa · 28 states
- Showy tick trefoil Desmodium canadense · 29 states
- Shrubby cinquefoil Dasiphora fruticosa ssp. floribunda · 23 states
- Sideoats grama Bouteloua curtipendula · 38 states
- Smooth oxeye Heliopsis helianthoides · 30 states
- Spotted beebalm Monarda punctata · 29 states
- Steeplebush Spiraea tomentosa · 22 states
- Swamp milkweed Asclepias incarnata · 37 states
- Swamp sunflower Helianthus angustifolius · 21 states
- Sweet Joe-Pye Eutrochium purpureum · 33 states
- Sweet coneflower Rudbeckia subtomentosa · 11 states
- Switchgrass Panicum virgatum · 43 states
- Tall blazing star Liatris aspera · 26 states
- Trumpet vine Campsis radicans · 33 states
- Virgin's bower Clematis virginiana · 27 states
- Virginia chain fern Woodwardia virginica · 24 states
- White heath aster Symphyotrichum ericoides var. ericoides · 26 states
- White meadowsweet Spiraea alba · 22 states
- White snakeroot Ageratina altissima · 23 states
- White turtlehead Chelone glabra · 22 states
- Wholeleaf rosinweed Silphium integrifolium · 16 states
- Whorled milkweed Asclepias verticillata · 30 states
- Witch-hazel Hamamelis virginiana · 33 states
- Yellow passionflower Passiflora lutea · 21 states
September in an Illinois native garden
September is a quieter month in Illinois: 78 of the state's 289 native plants flower in September, compared with 174 at the May peak. That makes these plants valuable for keeping color, and food for pollinators, going outside the main season.
2 start blooming in September, including White heath aster and Witch-hazel. 41 finish in September, including Blue vervain, Bunchberry and Butterflyweed, so this is the last chance to see them in flower.
63 of them grow in full or partial sun and 28 tolerate shade, so there are options for open beds and woodland edges alike. Sizes run from low plants like Black-eyed Susan and Buffalograss to trees such as Devil's walking stick and Maypop passionflower. For wildlife, 69 support pollinators, 51 provide food or cover for birds and 29 are caterpillar host plants.
70 of the 78 have a seed or plant listing we verified as the wild species. Be careful buying Black-eyed Susan, Common yarrow, Crimson-eyed rose-mallow: common listings for these are often a bred variety or a different species.
Good places to start
Verified wild-species listings that take sun and are widely native, so they are forgiving first plants.
- Cutleaf coneflower Rudbeckia laciniata · Sun, Part Shade, Shade · blooms Jul-Oct
- Little bluestem Schizachyrium scoparium · Sun, Part Shade · blooms Jun-Dec
- Big bluestem Andropogon gerardii · Sun, Part Shade · blooms Aug-Nov