Tennessee Nature Guide: September 2026
September turns Tennessee toward fall — the monarch migration funnels down the ridges and the Mississippi corridor, hawks stream past the Cumberland Plateau overlooks, goldenrod and asters gild the meadows, and the sorghum and apple harvests fill the mountain festivals. The first cool nights break the summer heat, and the earliest color touches the high Smokies.
What to look for this week
- Sandhill Cranes mass by the thousands at the Hiwassee Refuge near Birchwood while the last Christmas Bird Counts sweep the state, tallying eagles, cranes, and waterfowl.
- The Quadrantid meteor shower peaks in a short, sharp burst around January 3 — best after midnight from a dark Cumberland Plateau overlook at Pickett State Park.
- A planning week on the frozen plateau, but West Tennessee cold frames keep collards and kale growing — order seeds early before favorites sell out.
Birds This Month
September is the height of fall migration across Tennessee. The warbler wave peaks — Tennessee, Magnolia, Bay-breasted, Blackburnian, Chestnut-sided, Black-throated Green, American Redstart, and many more pour through the treetops, trickier to identify in their muted fall plumage. Ruby-throated Hummingbirds are still abundant at feeders early in the month, then thin out as they push south. Broad-winged Hawks stream over in kettles, and the Cumberland Plateau and mountain overlooks make fine hawk-watching.
Migrant shorebirds still work the West Tennessee mudflats and reservoir edges, Common Nighthawks continue their evening streams south, and Bobolinks, Dickcissels, and sparrows move through the fields. Scarlet and Summer Tanagers, Rose-breasted Grosbeaks, vireos, and thrushes drift south through the woods, and Chimney Swifts gather in massive pre-migration roosts, spiraling into chimneys at dusk. The first returning wintering birds — White-throated Sparrows and Yellow-rumped Warblers — arrive late in the month as the season turns.
What's Blooming
September is Tennessee's golden month, when the goldenrods and asters take over the meadows, roadsides, and old fields in a sweep of yellow and purple. A dozen goldenrods bloom together — tall, gray, and showy — alongside masses of New England aster, calico aster, white heath aster, and the late-flowering frost aster. Ironweed and joe-pye weed still hold deep violet and rose, and the prairies blaze with blazing star, gray-headed coneflower, and tall coreopsis.
The state wildflower, the passionflower (maypop), ripens its egg-shaped fruits along the fencerows, and along the streambanks the last cardinal flower and great blue lobelia linger. Jewelweed hangs orange in the wet bottoms, drawing the migrating hummingbirds, and trumpet creeper and wild morning glory climb the field edges. In the cedar glades of the Central Basin the late glade flora flowers in the thinning light, and the pollinator gardens hum with bees and the building monarch migration over the goldenrod and asters.
Garden This Month
September is the relief month in the Tennessee garden, when cooler nights ease the heat and the fall crops surge. The summer garden gives its last big harvest — pick the final tomatoes, peppers, okra, southern peas, melons, and winter squash, and pull spent plants to clean up the beds. The fall garden hits its stride: harvest broccoli, cabbage, lettuce, spinach, and the first frost-sweetened greens, and keep succession-sowing fast crops like lettuce, spinach, radishes, and turnips.
It is the prime month for several lasting jobs. Plant garlic and shallots toward month's end for next summer's harvest, sow cover crops — crimson clover, winter rye, Austrian winter peas — on emptied beds to build the soil, and divide and replant perennials, peonies, and spring bulbs. Plant new trees and shrubs now, as fall planting gives roots a head start before winter. Keep the fall seedbed watered, and start watching the forecast for the first frost, which returns to the high plateau and mountains by early-to-mid October.
Zone 6b (Cumberland Plateau & East Tennessee valleys): the first frost can come by early-to-mid October here, so the window is shorter. Harvest the last warm-season crops ahead of frost, tend the maturing fall greens, and plant garlic and cover crops as beds open.
Zone 7a (Middle Tennessee & Nashville Basin): the cool-season garden thrives. Keep sowing lettuce, spinach, radishes, and turnips, harvest the fall brassicas as they size up, and plant garlic toward month's end for next summer.
Zone 7b (southern Middle & West Tennessee): the heat finally eases. Continue sowing greens and root crops, set out a last round of lettuce and spinach transplants, and enjoy a long, productive fall before the late-October frost.
What's at the Farmers Market
September shifts Tennessee's markets toward the fall harvest while summer's last crops hang on. The headline crop is the apple — crisp new-season fruit from the Cumberland Plateau and East Tennessee orchards — and the fall sorghum syrup, cooked down at the mountain sorghum festivals, begins to appear. Muscadine and scuppernong grapes are at their peak, with their thick, slip skins.
The tables still carry late-summer tomatoes, peppers, okra, eggplant, sweet corn, and melons, now joined by the fall crowd — winter squash, pumpkins, sweet potatoes, greens, and the first fall lettuces and broccoli. Look for fresh pawpaws from the bottoms, cut flowers, and local honey. Choose apples that are firm and heavy with no bruises and store them cold, away from other produce, where they keep for months. Pick muscadines that are plump, dry, and unbruised and refrigerate them, eating within several days. Cure winter squash with hard rinds in a warm spot, then store cool and dry.
Night Sky This Month
September's clear, cooling nights are excellent at Tennessee's dark-sky places. Pickett CCC Memorial State Park and Pogue Creek Canyon, the International Dark Sky Park on the northern Cumberland Plateau, the high Great Smoky Mountains overlooks, and the Bays Mountain Park observatory near Kingsport run fall public viewing. The autumnal equinox near September 22 evens day and night, and the lengthening evenings bring earlier stargazing.
The sky is in transition. The Summer Triangle still rides high overhead with the Milky Way pouring through it, but the fainter autumn constellations are climbing the east — the Great Square of Pegasus, the chained figures of Andromeda and Cassiopeia's W, and within them the Andromeda Galaxy, the farthest object visible to the naked eye, an easy binocular smudge under dark plateau skies. Low in the south the dim water constellations spread out, and the Pleiades rise in the late-evening east, heralding winter. The printable Tennessee night-sky guide gives this year's planet positions and the best dark-sky sites for your region.
Butterflies & Pollinators
September is the great monarch migration month in Tennessee. The migratory super-generation streams south through the state all month, funneling down the Cumberland Plateau ridgelines and the Mississippi and Tennessee River corridors, nectaring heavily on goldenrod, asters, ironweed, and joe-pye weed to fuel the long flight to the fir forests of central Mexico. Roadside and prairie goldenrod stands can be alive with them on a good migration day.
The rest of the late-season fauna is still strong over the blooming meadows: cloudless and orange sulphurs stream through, gulf fritillaries work the passionflower of the west and middle of the state, common buckeyes, painted and American ladies, fiery and other skippers, and the last eastern tiger and spicebush swallowtails nectar at the asters. The question marks and eastern commas that will overwinter as adults are on the wing now, fattening up before hibernation. Leave the goldenrod, asters, and ironweed standing — they are the fuel that powers the monarch migration through Tennessee.
Trees This Month
September begins Tennessee's long, spectacular autumn, the color starting high and early. In the Great Smoky Mountains the first turning appears at the highest elevations — the mountain ash reddens its berry clusters on the spruce-fir summits, the yellow birch and American beech begin to gold, and the blackgum (tupelo) and sourwood flare the season's first scarlet across all elevations, always the earliest trees to turn.
The year's nut crop ripens and falls — hickory nuts, oak acorns, and husked black walnuts drop to feed the deer, turkeys, and squirrels stocking up for winter, and the persimmons soften toward ripeness after the first frost. The dogwoods redden their leaves and set their glossy red fruit, and the eastern red cedar of the glades hangs heavy with powder-blue cones for the waxwings and robins. Along the western rivers and at Reelfoot Lake the bald cypress just begin to bronze. The lowland forests still hold their summer green, but the turning has clearly begun in the high country.
Go deeper with the Tennessee guides
The complete Tennessee birding, native-plant, wildflower, and night-sky guides — or the whole year in one bundle.
Same month elsewhere: September in Texas · September in Utah · September in Vermont