Jayne Matthews thinks that most hairstylists are doing it wrong: “A person takes a pair of scissors and cuts the ends, maybe gives the hair some layers, but in general it’s like a big, shaped block on the head that needs to be blown into a manageable style.” Ms. Matthews — the co-owner of two salons in the San Francisco Bay Area, both called Edo — uses a straight razor as a carving tool instead of scissors. “I can carve petals into hair so it can have length but be lighter,” she says. “I consider it the difference between a hedge and a bonsai tree.”

These organic cuts, as she calls them, have garnered her a cult following of more than 82,000 on Instagram. Her signature look is a modern shag, heavy on the face-framing layers and bangs, inspired by Chrissie Hynde, Brigitte Bardot, Jane Fonda, Stevie Nicks and Patti Smith. Ms. Matthews, 47, charges $325 for cuts at her salons, the first of which she opened with her business partner, Chri Longstreet, in 1998. At that price, many clients get just one or two trims a year. “When you get these haircuts, they look cool and lived in,” she says. “You can wake up in the morning, maybe tuck it behind the ear, touch the bangs a smidge, and it looks good. The less you do, the better it looks.”

In 2014, after giving birth to a daughter, Ms. Matthews decided she’d try to get better at showing off her cuts on social media, practicing lighting and angles. Salons in Los Angeles and Portland, Ore., were soon asking her to come do cuts and trainings, and clients now routinely fly to the Bay Area to book with her.