The thief strikes in the dead of night, when victims in the southwest Minneapolis neighborhood of Linden Hills are sleeping. Creeping quietly into fenced yards and porches, the intruder nabs prized possessions, then disappears before dawn.

But instead of jewelry or electronics, this thief has an unusual specialty: gardens.

Flowers, bushes, trellises and statues have been taken from at least a dozen boulevards and yards, causing losses of thousands of dollars and putting local business and homeowners on high alert. To thwart the as-of-yet elusive thief, some are taking elaborate steps — establishing an e-mail alert system, installing motion detectors and keeping watch at night.

“It’s just a mystery,” said Jeanne Long, whose garden was raided three times last year and again last week. Long has lost plants and artwork, including a watercolor painting and a collection of antique pitchers displayed on her front porch.

It’s clear this is the work of a light-fingered green thumb who has an eye for the finer things.

“They know what plants they want — whatever is unusual,” said Abby Rutchick, who has been hit multiple times, losing about 20 ornamental bushes from her boulevard. “It really dampens your spirits.”

And the thievery isn’t confined to easily accessible flora in front yards. “The person actually came into our fenced back yard and took a 5-foot hibiscus out of the pot,” said Shari Davis. “How brazen is that?”

No one knows who’s behind the garden larceny, but a suspect was captured on surveillance camera last year, while pilfering plants — along with a wrought-iron trellis from France 44 Wine & Spirits. The video is grainy, but it shows a female, smoking a cigarette, with an accomplice — a little white dog.

Also appearing in the video was a car, a dark-colored, two-door Honda, said Chris Bixler, general manager at France 44, who shared the video with Minneapolis police. Unfortunately, “we couldn’t get a read on the license plate,” he said.

All of the targets are impatient to catch the thief.

“I’m completely furious and frustrated,” said Lyn Williams-Absey, owner of Brown & Greene Floral, which last week was robbed of freshly planted boulevard plants, including a dozen Dusty Millers and almost two dozen coleus. “In my front pot, I had a gorgeous hydrangea with ivy — she took pretty much of all of that, too.”

So far, Sunnyside Gardens has escaped the thief this spring, according to owner Mike Hurley. “We haven’t done a whole lot of planting yet this year,” he said, citing the growing season’s late arrival and rainy weather. But last year, his business was hit three times, losing hundreds of dollars’ worth of boulevard plantings. “We’re going to keep our eyes open. It’s a bad deal. I’d like to catch her.”

Jennifer Swanson, an aide to Minneapolis City Council Member Betsy Hodges, who represents Linden Hills, said Hodges’ office is encouraging victims to report all garden thefts, even small ones, to police. (The police liaison who has been working with Hodges’ office could not be reached for comment.)

Hurley, for one, suspects the thief is not stealing to outfit her own garden but is instead a shady businessperson, reselling what she digs up. “I’m guessing she’s a small-timer, with clients,” he said.

Rutchick, who is collecting data on the neighborhood plant thefts and organizing an e-mail network, is urging all home gardeners to be wary of buying “hot” hothouse plants.

“Know where your plants are coming from,” she said. “Look for tags.”

In the meantime, homeowners who have been targeted are on high alert. Rutchick said she’s taken to sleeping in a front bedroom, with her dog.

Long has installed motion detectors in her front yard, wired to an alarm inside her house.

“I sleep less. I find myself peeking out at all hours, especially in the early morning,” she said. “We’re kind of holding our breath.”