A few folks asked what makes a swampy song. Lol, I don't know, but I think Dixie Chicken is one. At least when the jam starts, the lead has a slight phase and it just sounds swampy with the bass and the other lead.
And that's all I know about that.
Reminder: just have fun!
Maybe some are inclined to be all scholarly about this.
Maybe it's a mix of geography (Atchafalaya, Honey Island, Congaree, Okeefenokee, Everglades, etc.) and/or the presence of gators, tupelo, cottonmouth, fire ants, the purple berries, etc), and/or the feel, the feel, the feel; the ritmos, the rhythms, strut and glide, the chanky chank, the thchopitoulas and tchfuncte, the stupefying heat; ima axe you a question - you gonna dance?
Tony Joe for sure (although listen, he was on the Pop Staples path), and Lowell George, some of the others mentioned above; my feel says it ain't got to do with rockabilly, nope, or some that other stuff above, but I ain't nothin, so what? Once upon I time, I lived in Louisiana, a stone's throw from the Tchefuncte.
Also, Gatemouth Brown, and south-of-I10-Sonny Landreth and the one and only Pops Staples:
('ol Carlos looks a little lost at the beginning of this but finds a little foothold, Gate brings it back and the horns!)
listen to that rhythm - that is whatumtalkin'bout
save the best for last:
Finally someone is putting words on this. Sharing info is normally enriching, I don't feel yours all scholarly (I'm sure mine appears closer).
There is a lot of specific musical things going on beside words and weather.
I was being playful with words, but it's part of my experience and thinking on swamp music, as far as what it sounds like to me. My version is only that; just one person's ideas.
But as you know, you don't have to be from Seville to play flamenco or fight your way out of the bear pit at Hunedoara to play gypsy jazz.
like all music, the influences go both ways - and never set in stone - musicians live and breathe their music, but are influenced by others; some a lot, some not so much.
So yes, the swamps of the Southern US states, particularly Louisiana and Mississippi, big influence, with Memphis and New Orleans and other stuff, like cajun folk music (from Canada!) zydeco, early rock shuffles, blues, ragtime and stride piano, accordion and concertina, washboard players, all go into the mix. What is described in the first two lines of Chuck Berry's "Johnny B. Goode"?
The feel of it is important, I think.
The Mamou Playboys - Mamou a little town surrounded by Louisiana rice fields, where the piney woods give way to prairie and then to marsh at the coast. Mamou has it's own special version of Mardi Gras.
the Muscle Shoals Rhythm Section - famous recording studio and session guys in what used to be a less populated area of Alabama, near the Tennessee River. They were originally referred to as the Muscle Shoals Swampers. I won't go into detail, here's the wiki link:
Guys like Chris Kenner, who wrote "I Like it Like That" and "Land of 1000 Dances" covered by Wilson Pickett, among others - and who, along with Fats Domino and Professor Longhair, were influences upon Dr. John, mentioned above:
Can't forget Queen Ida and her Bon Temps Zydeco Band:
One of my heroes is Jimmy Reed and his influence should not be denied, again the feeling - played everything like he had all the time in the world. That kind of harmonica playing?
back to the idea that you don't have to live there: Lowell George was a Hollywood boy - went to Hollywood High School. How he so tapped into that New Orleans rhythm and sensibility is double amazing. All kinds of wonderful. Here he is with an Allen Toussaint song (go look up Toussaint while you're at it) and the combination of Paul Barrere's guitar (another California boy; also mentioned above) with the excellent keyboard, bass and drums; wow!
..back where the OP started...