It was short and dramatic, but on Sunday, the Phantom Planter got his revenge.

Early this summer, guerrilla gardener Henry Docter surreptitiously planted 1,000 flowering plants in the long, tubelike entryway to the Dupont Circle Metro station. He did it, he said, to beautify the prominent but shabbily kept public space. Metro officials waited a couple of weeks before yanking out the hundreds of morning glories and other plants in July, prompting more than 10,000 supporters to sign a “Let Our Flowers Grow” petition.

And setting off Docter, an intense, lifelong Washingtonian who has been planting unauthorized flowers in public spots around the world for much of his 52 years. After July, he said, “I needed artistic closure.”

That closure wound up being a merger of performance art, civil disobedience and fodder for a bunch of strangers to have an impromptu Sunday chat about government power and the need for unexpected beauty.

Docter’s plan began to unfold at the Q Street entrance of the Northwest Washington station about 8:15 a.m., when the part-time lawyer appeared wearing an I’m-supposed-to-be-here-looking fluorescent vest and tool belt and carrying a big spool of rope. As a typical Sunday-morning scene of breakfasters and farmers-market shopping unfolded around him, the compact, bearded Docter busily wrapped rope around a bike rack on one side of the station and on some construction material on the other side, creating a rope-pulley system that crossed the top of the gaping Metro entrance like a spider web.

In about 30 minutes — attracting the attention of just a few Metro riders and a Metro employee who (unwittingly) helped him with the rope — Docter installed the pulley and then, with a brief assist from a young collaborator, hooked on the centerpiece: a 6-by-6-by-4-foot boxlike artwork, which was covered with quotes about the July flower standoff.

The box was then pulled to the center of the spider’s web. It dangled directly over the Metro entrance, above the middle escalator, which was closed for repairs.

Over the next 1 hour and 46 minutes, the 30-pound box of plastic tubing, clear tape and paper, which looked a little like an avant-garde Tinker Toy, was suspended, its sides plastered with online comments that readers had left about articles in The Washington Post and on the petition. Most supported Docter; a few didn’t.

Among the former: “Beautification of civic space should be applauded, not crushed,” “Metro should nurture flowers instead of mindless bureaucrats,” and “Metro seems to deal with most problems by asking ‘What would Joseph Stalin do?’ ”

And the latter: “We cannot allow this ‘phantom planter’ to inspire others,” “We value community input, but flowers attract rats,” and “We can arrest and imprison this ‘phantom planter.’ ”

For the first hour, reaction was subtle. Many people riding the escalator gave the box a brief, curious look, as if passing any old piece of public art. Many didn’t look up from their cellphone or newspaper.

But some lingered, staring. Among them were Dupont station regulars who could tell from the quotes that the box was related to the July standoff. At the time, Metro said that the cobblestone incline where Docter had planted was too steep and that many blocks were broken, making it dangerous for the plants to be maintained.

“He was trying to do something positive, and I don’t feel particularly threatened if someone plants flowers in a public place. I think we have bigger problems,” said John Pepper, a Maryland scientist who was on his way to a Quaker service in Dupont. “In some ways, it’s a trivial, silly thing, but in other ways it touches on deep themes — our ambivalence about the government’s uses and abuses of power,” he said.

Deborah Mendelson, a retired U.S. Agency for International Development worker, wasn’t using the Metro but rode the escalator to check out the box. With bright sunshine behind the white rope, the piece appeared to riders to be rising up from the dark station to hang in the air.

“I do think we need more humanity. I’m a big proponent of paying attention to beauty, instead of being umbilically connected to our phones,” Mendelson said, snapping photos.

During the first hour, a few Metro employees rode the escalator, glancing at the piece and then appearing to return to their posts.

One complained about paper that the artwork had been wrapped in that was left on the ground as trash; Docter grabbed it. Eventually more workers and Metro Transit Police officers gathered. Concerns were uttered about safety, calls were placed, and then an announcement was made that the subway entrance would be shut down as Metro figured out how to get the artwork down.

A couple of Transit Police officers wearing protective vests appeared. One with a German shepherd rode the escalator. A crowd gathered.

“That’s galvanized steel!” an officer said about the plastic piping, which Docter had painted black. “If it fell, it could kill someone; that’s not a report I want to write,” said another officer.

Philip Stewart, a Metro spokesman, issued a brief report later Sunday, noting that the “item was removed without incident” and that Transit Police were investigating.

The crowd seemed uninterested in any potential risk. Questions of spying and societal fear and Washington’s improved aesthetics all poured from the clear box suspended in air.

“I understand the security point, but this is the essence of art — courage. I applaud the courage it must have took to hang the thing. I love it,” said Joele Michaud, an art teacher who had walked through Dupont with her husband and two visiting friends to check out the Marine Corps Marathon. “But if this were rush hour, I think I’d hate it.”

A few took a critic’s stance. “He should have used bold-faced type,” one young man told his father as they gazed down.

Docter, meanwhile, saw none of this. Shortly after putting it up, he left. Partly, he wanted to avoid the police, but mostly, he said, his work was done.

“I just know there is something wrong with how we think about a lot of different things — living in fear, we’re all terrified about what’s going to happen next in life and not living in the here and now,” he said in a telephone interview. “Whether it existed for a second or an hour, the fact that it did will make almost everyone in D.C. smile. And that was the point.”