As a wise frog observed, it’s not easy being green. But, boy, Kermit — it’s sure fun to play a man-eating plant.

So say the puppeteers behind Audrey II, the star — with Jonathan Groff’s timid florist, Christian Borle’s sadistic dentist and Tammy Blanchard’s bullied Audrey — of the newly revived “Little Shop of Horrors.”

It takes four puppets of varying sizes to portray the horticultural horror in all her growing glory. Known as Pods 1, 2, 3 and 4, they range from a 12-inch sprout to a many-tendriled terror that’s as big as a Smart car.

“Construction was easy, but we lost a few people along the way,” jokes puppet designer Nicholas Mahon. “We just kept feeding the plant dead people until it grew!”

Mahon drew on designs by Jim Henson alum Martin Robinson, who created the original Audrey II nearly 40 years ago, when the Howard Ashman-Alan Menken musical opened off-off-Broadway.

“Marty gave specific directions about what each pod needs to be,” Mahon tells The Post. “Our goal was to put a little spin on it, but be true to the original version.” Pennsylvania-based Monkey Boys Productions helped him get the new puppets up and chomping.

Unlike the Audrey II who terrified Broadway in 2003 — whose hydraulic tendrils shot high out over the orchestra and came tantalizingly close to the balcony — this one’s Pod 4 is entirely people-driven. It arrived in two pieces, the only way it could get through the doors and up the narrow stairs of the Westside Theatre. The crew assembled it backstage.

“It’s one thing to have a great puppet,” Mahon says, “but you need great people to bring it to life.”

Eric Wright and Teddy Yudain are two of those people. They met at the Met Opera years ago, as understudy puppeteers for the Bunraku boy of “Madama Butterfly.” This is Yudain’s third “Little Shop,” and the hardest part, he says, is stifling his laughter during some of the more outrageous moments.

Wright operates the littlest of the “Little Shop” man-eaters, folding his 6-foot-2 frame under a desk so he can make his hand puppet quiver at her first taste of blood. Groff’s Seymour works the next-size puppet, while the puppeteers take turns animating Pod 3.

But it takes four hands and as many feet to make the biggest puppet come alive. Underneath Audrey II’s spandexed and painted fiberglass shell, the puppeteers belt themselves into their seats, “so we don’t go flying out,” Wright says. “We’re pretty animated in there.”

One of their biggest challenges is syncing Audrey II’s big mouth to Kingsley Leggs’ basso voice. “Feed me, Seymour!” the actor croons from a booth in the back of the theater, while the puppeteers — relying on in-ear monitors and lots of rehearsal — mirror his rhythms with Audrey II’s leafy jaw.

They say they’re still working on ways to make mayhem hilarious. Take the scene when — spoiler alert — the nasty dentist is fed, piece by piece, into the puppet’s mouth.

“We kept trying to find fun ways to eat his hand,” Wright says. They experimented with bouncing it around inside Audrey II’s mouth until finally sending it down the hatch. Now, they say, they’re trying to see how many times they can spin that fake hand in the air.

Says Wright: “We’re always looking for new ways to make it more amazing.”