Flower power as a slogan faded out with the 1960s. But as a decor motif, it's still blooming strong in the late Shirley Keller's house.

Keller adored bright floral prints. So much so that she covered virtually every room in her Golden Valley home — walls and ceilings — with bold flowered wallpaper, and upholstered her furniture in fabrics to match. Even her three-season porch is crowned with a tent-like canopy of flowered fabric.

"She loved color," especially vibrant blues, greens and yellows, said her son Frank Keller of New York City, who grew up in the house and remembers his friends' amazement when he'd first invite them over. "The house has always been a 'Wow!' "

His mother was "an interior designer at heart all her life," said Frank. A University of Minnesota graduate, she worked as a buyer in the millinery department at Dayton's before becoming a stay-at-home mom to her three children with her husband, Robert, a real estate developer. As her children grew up, she began decorating model homes and apartment buildings for her husband's projects, and acquired some design clients of her own.

But her own split-level home was her most completely developed creation. She and Robert built the custom home in 1960, and she lived there until her death in November at age 88.

Over those 55 years, Shirley redid her decor three or four times, her son said. "Each time she did it over, it got richer. She grew into a bigger, wider sense of color." The home's current flower-power look evokes the '60s but was actually created in the '80s, he said.

The Kellers built their home after falling in love with a Dutch Colonial in Edina that they didn't get. Instead, they found a half-acre lot in North Tyrol Hills and built a big split-level house with Dutch Colonial-inspired features, including barnlike dormer rooflines.

The home's original interiors had more of a "Minnesota look," said Frank, including plain walls and oak floors. "My mom's decor in the '60s was knotty pine with a brick fireplace and big, heavy wood beams," he said. Her love of pattern at that time ran to plaids and paisleys.

"Over time, she and a designer worked together to brighten the home," he said. "The brick was painted white and there was more of a floral theme."

The Kellers entertained frequently in their flower-festooned house. "They were very social and enjoyed sharing their house with friends," Frank said. There were small neighborhood parties, and bigger gatherings of industry friends, including general contractors, developers and bankers.

Shirley, a former homecoming queen from Cambridge, Minn., was a stylish hostess who was always impeccably dressed. "She took great pains with her appearance," Frank said. "She had a low-key but sophisticated look. She could wear blue jeans, a white blouse and a scarf and look great."

Shirley was a stickler for good manners and social graces, he said. "There was never an off-color word. She was very formal without being rigid."

And her home was her sanctuary. "She wanted it the way she wanted it," Frank said. "There was no cutting corners. She loved doing it, and she loved the results. She never wanted to move."

When the Keller house hit the market last week, its time-capsule decor sparked a flurry of conversation on social media. Some called it an "abusive use of wallpaper." Others swooned, calling it "spectacular … a perfectly preserved jewel box that showcases the owners' panache + joie de vivre."

Neutralizing the home's decor before putting it on the market wasn't really an option, said listing agent Josh Sprague of Lakes Sotheby's. "We discussed it. But removing all that wallpaper is a major endeavor. There are a lot of purists out there that want the midcentury bones and can see past the finishes and see the potential."

The home's best attributes include its layout. "It's very generous, especially for a split-level," Sprague said, with more than 3,800 finished square feet, large open spaces, three family rooms, four bedrooms, 3½ baths and lots of light. The half-acre lot, with the house set dramatically on a hill and a private backyard with a pond and waterfall, is another drawing card.

Two open houses have been well-attended, Sprague said. "We had a lot of neighbors who were curious about the house, who knew Shirley and loved Shirley and were curious about the inside."

Her son admits feeling a pang over parting with the house that's been in his family so long and that his mother infused with so much of her personality. "It speaks to a time," he said. "It's part of our history."

Josh Sprague of Lakes Sotheby's has the listing, 612-501-0252, josh@joshsprague.com.

Kim Palmer • @Stribkimpalmer.

Staff writer Aimee Blanchette contributed to this report.