In September, when Jil Sander sent models sliding down a Milan catwalk dressed in medleys of crisp, bright hues, color blocking (mixing two or more bright colors that don’t traditionally match) became high fashion’s seasonal idee fixe. The men of the 111th U.S. Open seemed to take note of the hard-to-miss summer trend, sprouting vivid pops of color at Congressional Country Club.

The golfer’s uniform, once a palette of safe, soft shades fit for the White House Easter Egg Roll, seemed to be turning into a Rothko spattering of acid greens, scarlet reds, fuchsia and tangerine. A revolution in color, happening in Bethesda.

“Golf is usually sweet colors, but on Thursday we saw a lot of the tart colors: dark orange, yellow, acid green,” said Woody Hochswender, a Golf Magazine style editor. “Golf is colorful in general, but even players that normally look conservative, like David Toms, wore scarlet red.”

Rory Sabbatini, Ian Poulter and Bubba Dickerson wore deep scarlet. Ben Crane wore a lime green polo, while Rickie Fowler wore a deep purple Puma polo and matching baseball cap. Davis Love III sported two trends, wearing Polo Ralph Lauren Pepto-Bismol-hued trousers and a black-and-white striped golf shirt. Rory McIlroy wore deep cerulean with crisp white trousers.

Like street fashion, Hochswender said, golf produces insular trends. Sponsors, not the whims of runway savants, dictate the prevailing trends by dressing the players. Bright colors have become part of the retail norm, with brands such as Nike and Puma pushing bold shades into the forefront of the golfer’s wardrobe. Brilliant pinks, in particular, are becoming commonplace. “Pink has become an important part of the Nike Golf seasonal color palette,” said Doug Reed, a global director at Nike Golf. “Vibrant colors, like our Rio, add a great hint of energy in a way that feels new, yet still athletic and appropriate.”

But then Day 2 began, and the brilliant color blossoming off the course faded as the men elected to wear sweet, syrupy pastel polos with cream and khaki pants. The energetic shades faded into McIlroy’s massive lead; while winning on the course, the golfer reverted to a tired robin’s-egg blue Oakley polo and dark khakis.

“Friday was a much more neutral field for some reason,” Hochswender said. “Who knows what tomorrow will bring?”