"(Dazed) Hey, the salamanders quit singing. (Giggles)" -Adyson
Adyson Sweetwater is one of the Fireside Girls in Danville Troop 46231.
She was a back-up singer with Gretchen in the song S'Winter ("S'Winter"). Immediately following Phineas and Ferb's treehouse fight with Candace and Stacy, as all the Fireside Girls are cheering. Adyson's mouth moves along with the line "Way to go!" ("Tree to Get Ready"). She was also one of the guitarists with Katie in the new version of The Flyin' Fishmonger ("The Flying Fishmonger").
When Phineas and Ferb built an Animal translator , she and Milly were explaining television to Isabella's dog, Pinky, unsuccessfully ("Interview With a Platypus"). Adyson, along with most other Fireside Girls, knows about Isabella's desire to marry Phineas ("That Sinking Feeling").
When Phineas and Ferb travel around the world in, took Isabella's place as troop leader after Isabella leaves with Phineas and Ferb. She ordered the other members and Clay Aiken to help get the party ready ("Phineas and Ferb Summer Belongs to You!"). When Phineas and Ferb build a bio-dome, she is shown to be comically accident-prone, getting heatstroke, being swept away by a current, and having a rock fall on her head ("The Great Indoors").
Adyson has straight dark brown hair with large bangs and a curve at the bottom. She has green eyes, rosy pink skin, and a red headband (which sometimes isn't seen in a few episodes). She wears a sleeveless uniform with a split in the collar and sides at the bottom, and high-top shoes, and in winter, a red shirt with a dent at the neck and long, bunchy sleeves, a longer brown skirt with an orange belt with yellow bow, black slip on shoes, and has an orange and red kerchef on her head in place of her hairband.
- Help Thy Neighbor Patch (About 52 as of "Isabella and the Temple of Sap")
- Aquatic Safety Patch
- Sewing Patch
- Tent Pitching Patch, Marshmallow Patch
- Aeronautic Patch
- Shrimp Net Repair Patch
- Sap Collecting Patch
- All Time Record Patch (6 patches, but, as of Fireside Girl Jamboree, the current record is 50 by Candace Flynn.)
- Mountain Moving Patch
- Rodeo Clown Patch
- Desert Tracking Patch, Rain-forest/Jungle Navigation Patch, Rock-climbing Patch, and Non-power Flight Patch
- Flier Delivery Patch (Twice "The Remains of the Platypus")
- Adyson is one of the characters to be an ambidextrous sprite. When she turns her head, her bangs swoop to the other side. Sometimes, the other side of her head can be seen in a few episodes.
- Her first cameo speaking line was in "Tree to Get Ready", while her first true speaking line occurred within "Isabella and the Temple of Sap", where she made a sarcastic comment on the "Help Thy Neighbor" patch.
- Her name was revealed in one of Swampy's Correspondence on the Phineas and Ferb wiki. The first on-screen mention was in "Isabella and the Temple of Sap", and her surname was revealed in "Fireside Girl Jamboree", and again confirmed in one of Swampy's Correspondence.
- Adyson is based on Jeff "Swampy" Marsh's grand daughter.
- She used to hold the record for "Most Patches earned in One Day", which was 6. Candace broke her record in "Fireside Girl Jamboree" with a massive total of 49 patches, 50 if the record patch is counted.
- She, along with Gretchen, are the only Fireside Girls not to have a red collar at the neck.
- As revealed in "Isabella and the Temple of Sap", she has a rather sarcastic sense of humor ("Let me guess, the Let's Help Phineas and Ferb patch?").
- Her surname was revealed in "Fireside Girl Jamboree". She is so far the only Fireside Girl besides Isabella and Candace to have her surname revealed.
- Adyson is the only regularly-seen Fireside Girl not seen in the Robot Riot! online game. She does, however make an appearence in the Isabella's Fireside Music Challenge game,
- "Lawn Gnome Beach Party of Terror" (First appearence)
- "Flop Starz"
- "The Fast and the Phineas"
- "Raging Bully" (Cameo)
- "Run Away Runway" (Cameo)
- "It's About Time!"
- "Out of Toon" (Cameo)
- "The Flying Fishmonger"
- "Mom's Birthday"
- "Out to Launch"
- "Jerk De Soleil"
- "Get That Bigfoot Outa My Face!"
- "Dude, We're Getting the Band Back Together"
- "Put That Putter Away" (Cameo)
- "Tree to Get Ready" (Speaking cameo)
- "The Ballad of Badbeard"
- "One Good Scare Ought to Do It!"
- "Interview With a Platypus"
- "Tip of the Day"
- "Day of the Living Gelatin"
- "Don't Even Blink"
- "Chez Platypus"
- "Thaddeus and Thor" (Cameo)
- "De Plane! De Plane!"
- "Oh, There You Are, Perry"
- "That Sinking Feeling"
- "At the Car Wash"
- "Phineas and Ferb Musical Cliptastic Countdown"
- "Bubble Boys"
- "Isabella and the Temple of Sap" (First name revealed)
- "Fireside Girl Jamboree" (Surname revealed)
- "Phineas and Ferb Christmas Vacation!" (Cameo)
- "Candace's Big Day"
- "I Was a Middle Aged Robot"
- "Robot Rodeo" (Cameo)
- "The Lemonade Stand"
- "Phineas and Ferb Summer Belongs to You!"
- "Wizard of Odd"
- "Rollercoaster: The Musical!"
- "The Great Indoors"
- "Phineas' Birthday Clip-O-Rama!"
- "Ask a Foolish Question" (Mentioned)
- "Tour de Ferb"
- "A Phineas and Ferb Family Christmas" (Cameo)
- "Tri-Stone Area"
- "The Remains of the Platypus"
- "Ferb TV"
- "The Last Day of Summer"