Gianna Henke’s preteen bedroom was a study in boring — a matching, if uninspired, mix of tan walls, tan carpet and leopard-print bedding. Then came high school, and with it Henke’s burning desire to shed her room’s parent-approved color palette for something more reflective of the teen she had become.

Out went the carpet, and in came the hot pink throw rug. Gone were the yawn-inducing beige walls, repainted with eye-popping yellow and orange. The animal-print comforter was swapped for a Hawaiian theme, the glare of megawatt overhead lighting replaced by the ambient glow of star-shaped lights dangling in the corners.

The days when a new beanbag chair, bedspread and pop poster sufficed as a remodel are long gone. Today’s teen rooms reflect a decorative savvy that rivals their parents’. If pictures of Ashlee Simpson or Orlando Bloom are present, they’re often on the back of the door, overshadowed by purple walls and black lights, tie-dye bedding, tattered curtains and markered walls — designs that could prompt well-meaning parents to double-dose on their Xanax but appeal to adolescents’ evolving sense of self.

Earlier generations weren’t subjected to the nonstop eye candy of quick-cut commercials and effects-laden video games that today’s teens experience. They weren’t bombarded with TV decorating shows, youth-oriented home furnishings stores or magazine articles on how to customize their own space. Celebrities weren’t same-age peers buying and decorating their own homes.

Today’s teens can’t escape the cultural tilt toward design and decor, and their bedrooms show it.

“What we’re noticing now is that teens are very, very advanced. They’re more adult than teens of previous generations,” said Rob Callendar, senior trends manager for Teen Research Unlimited in Illinois. “Instead of putting up concert posters or cutting things out of magazines, some are very interested in the very adult idea of getting furniture that reflects their own personality.

“Part of it is their own savviness. Part of it is there seems to be enough money that the parents can afford to and are willing to do this.”

Untapped market

And part of it is that home furnishings companies are finally opening their eyes to the $170-billion annual spending power of the country’s 35 million 12- to 19-year-olds.

The same stores that for decades have targeted grown-ups, college kids and parents-to-be are now pursuing teens. In the last couple of years, Urban Outfitters has expanded from being near college campuses to suburban malls. Pottery Barn and Crate & Barrel have each launched youth brands, offering items that not only speak to teens visually but do so in lingo that tries to be hip. A worktable with folding legs is a “flip-out desk”; a throw for girls is “furlicious.”

When Gianna Henke started high school, she jettisoned her preteen pastel bedroom decor in favor of a more mature scheme, complete with vivid colors, star-shaped pendant lights and plenty of candles.

“As kids grew up, there was this group spending more on home furnishings who had their own opinions of how they wanted things to look, and our Pottery Barn and Pottery Barn Kids brands weren’t it. They were a little bit funkier,” said Abigail Jacobson, public relations manager for PBTeen, the teen-oriented catalog and Web site that launched last year.

“Other industry sectors are catering to them big time — food, movies, electronics, clothes,” she added. “They expect it from furnishings retailers as well.”

PBTeen and Target are at the forefront of this growing market trend, offering free-spirited and offbeat designs at prices that acknowledge the fleeting nature of adolescent taste and the limits of parents’ willingness to pay for it. Think cargo-pocket pillow shams for $16, hot-pink telephones for $60, disco ball lamps for $33 and “diva” and “little miss drama” fun rugs for $70.

‘It’s just not me’

In the case of 17-year-old Alexandra Manzano of San Gabriel, Calif., it’s green drapes, purple walls and glow-in-the-dark stars on the ceiling — a design scheme that appealed to her interest in the stars, moon and sky.

“I kind of thought my room was boring because it was all white,” Manzano said of her old decor — the pencil-themed bed, shelves and Mickey Mouse rug she banished three years ago. Now, she says, “I love coming into my room. It’s kind of cool because it’s darker.”

Others don’t have it so easy. Alena Henke, Gianna’s 12-year-old sister, has had no luck convincing her mom to let her switch to the room she envisions: something “retro-y, like pop-artish,” she said. “You know, Andy Warhol paintings.”

ALEXANDRA MANZANO, 17, wanted her room to reflect her interest in the stars, moon and sky. She used glow-in-the-dark stars on the ceiling and green drapes and purple walls to give it a darker look.

Alena’s sensibility has been informed and shaped by TV, specifically VH1 retro shows such as “I Love the ’70s” and decorating makeover programs on HGTV. Right now, Alena’s room is “garden-y,” with lemon yellow walls and floral, picket fence wallpaper. Painted on the wall above her bed: a Tinker Bell-size fairy.

“It’s kind of really girly, and it’s just not me,” the Arcadia, Calif., eighth-grader said with a sigh. For now, Mom won’t go to the expense of changing Alena’s room because she suspects her daughter will only want to change it again.

Let her, says teen psychologist Michael Bradley.

“A teenager’s job is to figure out who they are and to break apart from the parents in an appropriate way, so the bedroom becomes the initial outpost of this new adult that’s emerging through the adolescent years,” said Bradley, author of the books “Yes, Your Teen Is Crazy!” and “Yes, Your Parents Are Crazy!”

“The point of adolescence is identity exploration. They try on 10,000 different hats to see what fits and what doesn’t,” he said. “You want to encourage them to do crazy, zany stuff. That’s healthy.”

For the most part, it’s the girls who want to applique their curtains, customize their armoires and put their personal stamp on their space. It’s the rare adolescent boy who cares about the color of his lampshade or the shape of his pillows.

Most are content to hang a poster, prop a trophy on the shelf and call it a done deal. They don’t seem to care. Their rooms are nondescript crash pads. Overhauling the decor has always been much more of a girl thing.

“This whole generation has lots of stuff, including their own cellphones, and definitely their own voice in how they want their rooms to look,” said Nan Sloan, contributing designer to HGTV’s “Decorating Cents.” “Particularly the girls who grew up with these purple and pink frilly little rooms, now they’re early adolescents. They want to make a statement.”