Quick answer: 39 native South Dakota plants have a recorded bloom range that includes August.
39 species
- Arctic brome (Kalm's brome) Bromus kalmii · 5 states
- Big bluestem Andropogon gerardii · 25 states
- Black-eyed Susan Rudbeckia hirta · 42 states
- Blue grama Bouteloua gracilis · 15 states
- Blue vervain Verbena hastata · 11 states
- Bunchberry Cornus canadensis · 7 states
- Closed bottle gentian Gentiana andrewsii · 10 states
- Common evening primrose Oenothera biennis · 12 states
- Common gaillardia (blanketflower) Gaillardia aristata · 11 states
- Common sneezeweed Helenium autumnale · 13 states
- Compass plant Silphium laciniatum · 11 states
- Cup plant Silphium perfoliatum · 17 states
- Fall obedient plant Physostegia virginiana · 21 states
- Fireweed Chamerion angustifolium · 28 states
- Flowering spurge Euphorbia corollata · 6 states
- Grayhead coneflower Ratibida pinnata · 12 states
- Great blue lobelia Lobelia siphilitica · 32 states
- Harebell Campanula rotundifolia · 25 states
- Indiangrass Sorghastrum nutans · 19 states
- Little bluestem Schizachyrium scoparium · 23 states
- Mexican hat Ratibida columnifera · 17 states
- Partridge pea Chamaecrista fasciculata · 13 states
- Prairie blazing star Liatris pycnostachya · 16 states
- Prairie dropseed Sporobolus heterolepis · 11 states
- Prairie goldenrod Solidago nemoralis · 7 states
- Prairie ironweed Vernonia fasciculata · 7 states
- Rocky Mountain bee plant Peritoma serrulata · 22 states
- Showy goldenrod Solidago speciosa · 6 states
- Showy tick trefoil Desmodium canadense · 21 states
- Shrubby cinquefoil Dasiphora fruticosa ssp. floribunda · 15 states
- Sideoats grama Bouteloua curtipendula · 25 states
- Smooth oxeye Heliopsis helianthoides · 12 states
- Smooth rose Rosa blanda · 8 states
- Smooth sumac Rhus glabra · 34 states
- Swamp milkweed Asclepias incarnata · 25 states
- Switchgrass Panicum virgatum · 24 states
- Tall blazing star Liatris aspera · 11 states
- Whorled milkweed Asclepias verticillata · 6 states
- Wood lily Lilium philadelphicum · 7 states