Tough turf

The putting greens at Oakmont Country Club are the course’s most famous, most manicured and most difficult feature. So it may come as a surprise that the coiffed grass on those greens is, in fact, a weed.

There are many varieties of the so-called poa annua, also known as annual bluegrass, but Oakmont’s is distinctive.

“It’s a perennial poa annua, and it’s very unique to this site here at Oakmont,” said course superintendent John Zimmers.

When the U.S. Open, considered by many to be the toughest of golf’s four major championships, comes to Oakmont this week, those uber-fast putting greens will stand out.’

Oakmont’s densely packed poa has a thinner leaf blade than the grass found on most greens. This strain creates less friction than other grasses, and it sends golf balls scampering across greens like pucks on freshly Zamboni-treated ice.

“The grass has evolved here and been selected through maintenance over the years,” said David Delsandro, director of U.S. Open operations and projects. “It’s a putting surface that’s really not replicated anywhere else. So we’re able to do different things that allow us to produce the green speeds and the firmness that other grasses aren’t able to tolerate.”

John Zimmers, Oakmont's course superintendent, talk about maintaining the greens. (Nate Guidry/Pittsburgh Post-Gazette)

As a result, he said, Oakmont cuts its greens much lower than most courses; it mows and rolls that turf more frequently; and it is able to maintain the grass at a drier state.

Add to that the greens’ sloping architecture and higher elevation, and you have a recipe for a tough golf outing.

“The grass has evolved and selected itself over the years of this high-intensity maintenance to be able to withstand some of these mechanical stresses and pressures we put on it on a daily basis,” Delsandro said.

This poa is not the product of Pittsburgh’s climate alone, since this variety didn’t grow at the adjacent Oakmont East course (now closed) and nearby Phipps Conservatory and Botanical Gardens.

Rather, it appears to have adapted to the elaborate maintenance program Zimmers oversees. On a recent morning, Zimmers said it would take the grounds crew as much time to care for 3.5 acres of greens as it would to cut about 30 acres of fairways.

“We mow the greens two, three times in the morning, pretty much every day,” he said. “As we get closer to the championship, we’ll actually mow them in the evenings as well.”

The mowers themselves are a work of art. Oakmont devotes more than 20 mowers just to the greens and sharpens them every day.

“We all know if you have a bad razor on your face or on your legs, it doesn’t feel good,” Zimmers said. “That’s the same exact thing for the grass.”

The greens’ spa treatment also includes rolling the grass; adding fertilizer; brushing off dew and sand with a dew whip; sending soil and grass samples to a lab for testing; syringing, or cooling off, the grass; changing the hole location every day; and more. Because this variety can’t currently be bred, and you can’t buy Oakmont’s poa, the club maintains a collection of plugs from the process of aerating the greens.

“These greens have been like this really from day one,” said USGA executive director and CEO Mike Davis during a press conference at the club. “If you go back [to] the 1935 U.S. Open that was played here, the players were complaining incessantly about the greens being too fast. That was 1935. In fact, some of them almost boycotted and didn’t want to play.”

Oakmont founder H.C. Fownes was known for testing speed by dropping a ball on the back of the second green and watching as it rolled off. Preferring a more scientific measurement, Edward Stimpson, a spectator and golfer watching the 1935 tournament at Oakmont, developed a ramp-like device to measure green speed.

Stimpson “decided he thought the greens were too fast, but we needed a way to measure,” Davis said. “And that was the birth of the USGA Stimpmeter.”

The since-updated Stimpmeter remains the association’s go-to tool for measuring green speed. The reading is calculated by taking the average distance a golf ball rolls on a green.

“On a normal day here at Oakmont, our green speeds will be close to 13 [feet per roll],” Zimmers said. “On average, a golf course, they’re probably more close to 10. So it’s just part of our culture here, part of our history.”

For those watching the tournament in person and eager to test Oakmont’s greens for themselves, a replica of the 18th green will be available for spectators.

So what would Zimmers, who knows Oakmont’s greens like few others, recommend for a putter navigating these slippery surfaces?

“You’ve got to keep the ball in the fairway,” he said. “You’ve got to be on the greens. You’ve got to be below where the holes are so you’re not putting downhill to them, and you’ve got to stay out of the bunkers.”

At Oakmont, that’s easier said than done.

Elizabeth Bloom: ebloom@post-gazette.com, 412-263-1750 and Twitter: @BloomPG