In the darkness, the trees form black, flat columns rising from rivers of twinkling lights. The tiny illuminations — 20,000 of them hovering above the forest floor — shift colors and patterns, as if someone were turning a huge kaleidoscope. The crickets are noisy; the people are silent.

On this warm September night, there are a lot of visitors to Longwood Gardens, the du Pont estate in Kennett Square, Pa., known for its horticultural showmanship, from the large conservatory displays to the beautifully kitschy Italianate fountains.

But on this night, they are drawn not so much to the brassy fountain show as to the ethereal lights in the woods, the “Forest of Light,” and the seven other installations at Longwood by British light artist Bruce Munro.

Munro is to fiber optics, you might say, as Dale Chihuly is to blown glass and Christo to wrapped fabric, an artist whose outdoor installations intensify their subject landscapes. At Longwood, the numbers alone suggest that Munro has succeeded.

With relatively little publicity, the exhibit “Light” has drawn more than 300,000 visitors over the summer. It closes Sept. 29.

One of the installations is not light-driven and meant to be seen before dark: “Waterlilies” is a series of huge lily pads fashioned from 65,000 recycled CDs. In scale and form, they evoke the exotic and monstrous Victoria lily, a water plant with pads six feet across.

Another of Munro’s works, “Field of Light,” spreads across the grassy hill on the far side of a finger lake: Here a mere 7,000 lights flicker, this time in frosted glass spheres (the “Forest of Light” bulbs are clear glass). Beyond the lake, the colors are a tad more intense, they shift in more rapid waves, and they seem to evoke mythic fireflies — fauna to the flora of the “Forest of Light.”

Visitors find yet another experience at “Water Towers,” 69 stout pillars about six feet tall, each fashioned from 252 plastic bottles filled with carbonated water and strands of optical fibers. They resemble giant crystal tumblers whose colors change to the sound of music. The work is set on the edge of Longwood’s 42-acre wildflower meadow, and on this night the surreal nature of the towers is intensified by a mist that comes tumbling down the field while the sky, improbably, remains clear and star-filled.

I want to like “Water Towers” more, but I can’t get beyond what was for me the deeper experience of the “Forest of Light.” The hand-blown glass bulbs rest on stalks set amid the woodland floor; some are upright, some skewed, some set a few inches aloft, others at three feet or more. The strands of fibers that feed each stalk glow as well, so that the ground is matted with faintly luminescent spaghetti. As strange as the detail is, it is the sheer scale of the work that really touches the imagination: The lights form a river of twinkling and changing colors, following the rising topography before looping back down the hill. Illuminations — one thinks of Las Vegas — can be sensationally tawdry. By contrast, the “Forest of Light” is strange and touching and authentic. It is a phenomenon of opposites, organic and synthetic, familiar and otherworldly, tangible and dreamlike.

As I am touring the installation with Munro, we notice a young woman who is looking at Munro with a mixture of awe and adulation. She is a student of choreography, she tells him, and Munro, characteristically, speaks not of himself or the artwork per se but of the parallels to dance.

Munro is 53, voluble and large-hearted. He seems drawn to the best in people, like a religious man, and his brain appears to be constantly engaged on both sides. He can talk at length about the mechanics of his installations and the metaphysical inspiration behind them.

His recurring motif of lights on stalks grew out of an experience as a young man in Australia, where, after art school in England, he worked for a company that made lights and signs for businesses. He was in the bush when a rare rainstorm appeared. He felt a life force rising from the dusty desert. Yes, he knows this makes him sound like an Earth child. This is how he sees the world.

At a reception before the tour, he talked about his journey as an artist. He did an exhibition at the Victoria and Albert Museum in London and, more important, in a field he bought next to his home in western England. The installation of 15,000 lights was a costly and labor-intensive project, but one he promised himself after his father died. People using the country footpath next to it were mesmerized. “I was like a lighthouse keeper. I would flick a switch and just let people enjoy the field. What amazed me was the reaction; I was really overwhelmed.” He took a sip from his glass, using the stirrer as a straw. “I felt, there’s a message here, about simple things, about positive life thinking. That sounds dated in today’s world, but I’m fed up with the cynicism.”

The Longwood show is his first exhibition in the United States, and it takes on a stunning scale. The show spans 23 acres and took Munro’s crew of eight more than two months to install, even with the help of an army of more than 100 volunteers. The “Field of Light” work alone has almost 90 miles of optic fibers.

With its resources, Longwood has been good for Munro, but Munro has been good for Longwood, too. Since it opened June 9, the show has boosted Longwood’s attendance and admission revenue by 50 percent. “We knew it would be well received, but we knew we were also taking a risk,” said Paul Redman, Longwood’s director. “As Bruce was installing the exhibit we all knew we had something far more special than we ever imagined.”

Redman tried to get the artist to prepare for his American debut. “We said, ‘Bruce, we hope you’re ready, because you may be on the road [to stardom] here.’ When that exhibit opened, he was a rock star. He was a rock star.”

Read past columns by Higgins.

Plan your trip

The Longwood Gardens exhibition “Light” by Bruce Munro requires special tickets and is open for evening viewing Wednesday to Saturday this week and next. Hours have been extended until 11 p.m. on those days. The final date, Sept. 29, requires a special ticket that includes the Longwood fireworks and fountain display. 610-388-1000. The gardens are off U.S. Route 1 in Kennett Square, Pa.