Maryland Nature Guide: September 2026
September is the great fall-migration month in Maryland — warblers and hawks stream south, monarchs concentrate along the coast at Assateague, the asters and goldenrods peak, and the markets hold the bridge from summer's tomatoes to autumn's apples as the air finally cools.
What to look for this week
- The Chesapeake waterfowl winter peaks — Tundra Swans, geese, and rafts of canvasback and redhead crowd Blackwater NWR as the Christmas Bird Counts wrap up across Maryland.
- The Quadrantid meteor shower peaks in a short, sharp burst around January 3 — watch after midnight from a dark site like Assateague Island or the Garrett County highlands.
- A planning week for Maryland gardeners — review last season and order seeds early before the popular varieties sell out, while the ground sits frozen.
Birds This Month
September is one of the two best birding months in Maryland, when fall migration crests. The woods and edges fill with southbound warblers in subtler fall plumage — American redstart, magnolia, black-throated green, Cape May, blackburnian, bay-breasted, and blackpoll — along with vireos, thrushes, tanagers, and flycatchers. The coastal points and the C&O Canal teem at dawn, and migrant ruby-throated hummingbirds still work the jewelweed and feeders.
This is also hawk-migration season. Ridge lookouts and the Bay's funnel concentrate streaming broad-winged hawks (peaking mid-month in great "kettles"), sharp-shinned and Cooper's hawks, ospreys, bald eagles, American kestrels, merlins, and peregrine falcons, the last hunting the shorebird flocks at Assateague. The Eastern Shore impoundments still hold migrant shorebirds, and the first wintering sparrows and the earliest returning waterfowl arrive late in the month. The skies are busy from coast to mountains.
What's Blooming
September is the climax of Maryland's late-season wildflowers, the meadows and roadsides a sea of purple and gold. The asters peak — New England, calico, heath, and blue wood asters — woven through the goldenrods (tall, gray, blue-stemmed, and the seaside goldenrod blazing on the Assateague dunes). With them stand the last ironweed, Joe-Pye weed, boneset, sneezeweed, wingstem, and swamp sunflower.
The tidal marshes of the Chesapeake glow with seaside goldenrod, marsh fleabane, and the russet of ripening cordgrass and wild rice, and the freshwater wetlands hold the last cardinal flower and blue lobelia. In gardens, asters, sedum, Japanese anemone, goldenrod, sunflowers, and chrysanthemums carry the bloom into fall. The aster-and-goldenrod nectar is the critical fuel for the migrating monarchs now streaming down the coast — these last flowers of the year power the long journey to Mexico.
Garden This Month
September is a turning month in the Maryland garden, when the heat finally breaks and the fall garden takes over. The summer crops slow but still produce — pick the last tomatoes, peppers, eggplant, beans, and melons — while the cool-season planting hits full stride. Keep sowing fast greens, spinach, lettuce, arugula, radishes, and turnips, and tend the broccoli, cabbage, kale, and collards set out in late summer for a fall harvest that sweetens with the first frosts.
This is the month to plant garlic toward its end for next summer's crop, and to sow cover crops of winter rye or crimson clover on emptied beds to protect and build the soil. In the ornamental garden, plant and divide perennials in the cooling soil, plant spring-flowering bulbs — daffodils, tulips, crocus — from late month, and start a fall lawn renovation. Clean up spent and diseased plants, but leave seed-heads and standing stems for the birds and overwintering insects. The cool, settled weather makes September one of the best gardening months of the year.
Zone 6b (western Maryland & the Frederick uplands): the first frosts loom. Harvest the warm-season crops before the early mountain frost, finish fall greens, plant garlic and spring bulbs, and cover tender crops on cold nights late in the month.
Zone 7a (central Piedmont & the Baltimore–Washington corridor): the fall garden hits its stride. Keep sowing fast greens and radishes, harvest the cooling summer crops, plant garlic and cover crops late in the month, and divide and plant perennials in the cooling soil.
Zone 7b (lower Eastern Shore & the Bay's warming edge): the long, mild fall begins. Plant a full fall garden of greens, brassicas, and roots, set out cool-season transplants, and enjoy the productive autumn this warm zone allows well into November.
What's at the Farmers Market
September markets in Maryland bridge summer and fall. The last of the warm-season crops carry on — tomatoes, peppers, eggplant, sweet corn, beans, cucumbers, summer squash, and the late melons — while the autumn crops arrive: winter squash, pumpkins, sweet potatoes, broccoli, cabbage, kale, collards, and the first crisp fall apples from western Maryland and Frederick County orchards. Grapes and the last peaches finish the stone fruit.
The Chesapeake's blue crabs are heavy and full now — many say the best eating of the year as they fatten before winter. Choose winter squash and pumpkins with hard, unblemished rinds and an intact stem, and store them in a cool, dry place where they keep for months. Pick apples that are firm and heavy, and store them cold and away from other produce. Keep ripe tomatoes on the counter, and buy and eat sweet corn the same day. The markets are full and varied as the season pivots into autumn.
Night Sky This Month
September's autumn equinox near the 22nd brings day and night into balance and opens the cooler, often clearer nights of fall over Maryland. The Summer Triangle of Vega, Deneb, and Altair still rides high after dark, but the autumn constellations rise in the east — the Great Square of Pegasus and the chain of Andromeda, carrying the Andromeda Galaxy (M31), the most distant object visible to the naked eye, an easy binocular target from a dark Maryland sky.
There is no major meteor shower at its peak this month, so September favors the deep-sky objects in the cooling, steadier air — the Milky Way through Cygnus still arches overhead, the Double Cluster in Perseus rises in the northeast, and the harvest moon near the equinox lights the marshes and fields. The dark horizons of Assateague and the lower Eastern Shore give the clearest views. The printable Maryland night-sky guide lists this year's planet positions and the best dark-sky sites for the season.
Butterflies & Pollinators
September is monarch month in Maryland. The great fall migration funnels down the Atlantic coast, and the butterflies concentrate spectacularly at the coastal points — Assateague Island and the Eastern Shore peninsulas can hold streaming, roosting monarchs on a good northwest-wind day, fueling on the seaside goldenrod and aster before crossing toward Mexico. Watch the dune flowers and field edges on clear, breezy days for the season's defining wildlife event.
The migration carries others south too — cloudless sulphurs, painted and American ladies, red admirals, common buckeyes, and question marks drift down the coast with the monarchs, and the meadows still hold fritillaries, sulphurs, and late skippers nectaring on the goldenrod and aster. The late-season flowers are crowded with butterflies on warm afternoons. This is the month to plant or protect native asters and goldenrod — they are the essential last fuel for the monarchs and all the late migrants leaving Maryland for the south.
Trees This Month
September begins the long Maryland autumn in the trees. The first color comes early — the black gum (tupelo) burns scarlet and crimson, often the first tree to turn, joined by the early reds of sumac, Virginia creeper, the flowering dogwoods (now hung with glossy red fruit), and the yellowing black walnut and tulip poplar. The spicebush turns clear gold in the understory.
The mast crop falls in earnest — the acorns rain down from the white and red oaks, the hickory nuts drop, and the black walnuts litter the ground, feeding the squirrels, deer, turkey, and the gathering birds. The American holly berries begin to redden on the Coastal Plain, and the red cedar sets its blue cones. On the western mountains, the sugar maples and birches start to color in the cool nights of Garrett County, where Maryland's fall display begins earliest and runs strongest. The great turning is just beginning.
Go deeper with the Maryland guides
The complete Maryland birding, native-plant, wildflower, and night-sky guides — or the whole year in one bundle.
Same month elsewhere: September in Massachusetts · September in Michigan · September in Minnesota