The couch in Greg Berlanti’s spacious office on the Warner Bros. lot is crowded with needlepointed throw pillows, all gifts from his mother — one for each of his series, the successes along with the noble failures. There’s “Everwood,” “Political Animals,” “Dirty Sexy Money,” and “Arrow,” festooned with, yes, a black plastic arrow.

With this season’s pickup of three new shows from Berlanti Prods., spanning three networks — CBS’ “Supergirl,” NBC’s “Blindspot” and the CW’s “DC’s Legends of Tomorrow” — soon there won’t be room for guests to get comfortable.

Luckily, the pillows take a while to make their way to his couch. “There’s a woman who does the needlepoint, and then my mother ‘produces’ them,” he says with a laugh. “She just feels like she makes them.”

But that’s not his producing style.

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Berlanti takes a hands-on approach to all of the shows in his stable, and over the years has assembled a trusted team to help him execute — Marc Guggenheim, Andrew Kreisberg and Ali Adler, among them — which DC Comics chief content officer Geoff Johns jokingly calls his “Justice League.”

“Honestly, I’m so reliant on others,” Berlanti says. “It’s the long-term relationships I’ve had that allow me to do multiple things, because you have a shorthand with these people.”

With a total of six shows now in production — the Debra Messing vehicle “Mysteries of Laura” on NBC, along with the CW’s hits “Arrow” (starring Stephen Amell) and “The Flash” (headlined by Grant Gustin), not to mention his upcoming feature “Pan” (due in October) — he’ll need superpowers of his own to manage his staggering workload.

But nervous network execs needn’t worry. The 42-year-old wunderkind says he discovered long ago — going back to his days on the WB’s “Dawson’s Creek,” where he had a meteoric rise to showrunner — what it takes to succeed in the role.

“I learned that I really rely on other writers — that I can break stories quickly, but I can’t write quickly,” he says. “I learned that it’s OK that I’m not great at everything, that there are a lot of things that I may never be as good at as some of the other people I hired. Don’t be threatened by that. Co-opt that. Be good at the stuff you’re good at, but also know what you’re not as strong at.”

So he focuses his time and energy on where he can make the most impact: developing stories, editing, casting. You’ll rarely find him on set.

“I don’t have to be on every phone call for everything that gets approved, but I need everybody to know — whether it’s a junior executive at a network, an actor, a production person or a department head on one of the shows — that they can always reach me,” he says.

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His priority is always quality: “I don’t want to do more just to do more it if it’s not good,” he says. And the frustration, he admits, is that he can’t always be where things are going well — it’s the problems that draw his attention. And certainly, the debuting shows will be his focus.

“The first thing I’m thinking about in the morning, and the last thing I’m thinking about at night, are usually the newer ones, because you haven’t figured out the algorithm yet,” Berlanti says. “From the moment the shows get picked up until we have an episode that’s as good as the pilot, I’m usually stressed about how we can do it again.”

That comicbook shows are now a success seems a no-brainer, given that they’re all that seems to be scoring in movies, but “Arrow” was a smallscreen breakthrough. And everyone involved credits Berlanti, a self-professed comicbook geek. It was his passion for the source material that infused the show — along with its successor, “The Flash” — with its emotional heart, compelling narrative and whiz-bang visual effects that have stirred fans and critics alike.

“The first thing I always do is ask, ‘What is the show if you took away (super) powers?’ ” he says. “I only know, as a fan, what I would want to see.” Thanks to his track record, Berlanti has become DC’s go-to producer for its comicbook archive. Cue “Supergirl.”

A comics heroine has been long overdue — even Berlanti’s nieces have been nagging him — so when DC pitched him on the concept, he was intrigued. But rather than keep the show in the vein of what had been done before, he wanted to take a proportional leap. “With what we accomplished and learned from ‘The Flash,’ ” he says, “if we could do that on an even larger scale, on a bigger network, what would that look like?”

CBS, he reports, jumped at the chance. He says entertainment prexy Nina Tassler fell in love with “Supergirl” at the pitch meeting, so much so that she started to cry. “It didn’t matter at that point what they were going to pay for it,” he says. “That’s who you want buying the show.” (Despite the rumor mill, Berlanti says there was never a chance of the show moving to the CW. Plus, he adds, “We would never have been able to afford the kind of budget we have.”)

As with “The Flash,” Berlanti has insisted “Supergirl” invest heavily in visual effects, and Johns calls the money well spent.

“When people see the pilot, they’ll be blown away by what’s accomplished on television,” says the DC content topper. “But Greg knows that it’s not just about spectacle. It has to be about heart; it has to be about humor.”

Casting is paramount to Berlanti: He calls the show’s star, Melissa Benoist, the “Annie Hall” of superheroes.

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“The most important decision you can make as a showrunner when you’re doing a pilot is who’s in it, and who’s directing it,” he says. “If we had not found her, I would have said, ‘I don’t want to make this.’ ”

As for “Blindspot,” which has landed the plum timeslot behind “The Voice” on NBC’s Monday night lineup, Berlanti was swayed by writer Martin Gero’s passion.

“There are very few times when someone pitches you a show and you think to yourself, ‘All I have to do is call the studio and say, ‘Buy this,’ Berlanti says. “My job in those circumstances is to protect the person through the process.” And the finished pilot, he notes with pride, is exactly as Gero pitched it.

For such an obvious smallscreen fan, it’s ironic that Berlanti now says he didn’t always think he wanted to do television. It was his famous friendship with Julie Plec (“The Vampire Diaries,” “The Originals”) back in college that drew the budding theater writer into the TV world, and introduced him to Kevin Williamson, who was then running “Dawson’s Creek.”

And it was his spec script for “Everwood” that brought him into the Warner Bros. family, where he first cut his teeth as a budding producer — and now has a lucrative overall deal through 2018. Recalls Warner Bros. president Peter Roth: “I loved it so much I called my entire team that afternoon and said, ‘We have to produce this show.’ I thought it was the perfect metaphor for what happened after 9/11.”

Now Roth calls Berlanti part of the foundation of the company, heaping praise on him as a “brilliant visionary,” while the CW president Mark Pedowitz calls himself a “huge fan.”

“Greg has done an amazing job of reinvigorating the superhero genre on television, and opening the DC canon to fans in a different way,” says Warner Bros. chairman-CEO Kevin Tsujihara. “He is incredibly talented, and we are fortunate to be in business with him.”

Sarah Timberman, exec producer of “Masters of Sex,” “Justified,” “Elementary” and other shows, saw Berlanti’s career skyrocket after he joined “Dawson’s” at age 25 in its second season, when she was the top development exec at Columbia TriStar TV.

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“Based on what we saw in Greg in his first week on ‘Dawson’s Creek,’ I’m not surprised he has six shows on the air,” Timberman says. “He had an enthusiasm for writing that was totally infectious. He was sure-footed and witty, and mature beyond his years as a writer.”

Despite Berlanti’s humility (“We’ve had the opposite year, too, where we’ve had a lot of things cancelled,” he cautions), his success in TV seems well established. That leaves features as the next rung on the career ladder. He wrote a script for a “Green Lantern” movie he’d hoped to direct back in 2010, but the studio ultimately went with another version, which disappointed at the box office. Last year, he brought onboard former WB exec Sarah Schechter as president to help shepherd Berlanti Prods.’ film projects. “It’s been an awesome relationship,” he reports.

Besides “Pan,” he’s in development on a few other projects, and he hopes to make another run at translating a superhero to the bigscreen.

“There are definitely characters who are still out there who haven’t been explored onscreen yet,” he says. “It feels fated that I’ll hopefully work on one

of those.”

And this time out, he’s got all the support he needs.

“What Greg wants to do, he’ll accomplish,” says Johns, “and he’ll accomplish really well. (Having) him on DC characters is always good for us.”

Memo to Mom: Time to order a quilt.