The Twin Cities area has experienced a wave of bonsai banditry as thieves have crept into yards in the middle of the night to steal beloved miniature trees worth thousands of dollars.

Hopkins police reported that one home was hit twice — on Aug. 25 and Sept. 5 — with the thieves making off with potted trees that had been kept outdoors but within a fenced area.

The owners reported that the stolen trees included 80-year-old hornbeams and a ponderosa pine estimated to be more than 250.

Hopkins police Sgt. Michael Glassberg said one of the stolen trees was worth about $7,500 and the other was worth about $6,000.

Glassberg said the trees were not visible from the street, leading police to believe that the criminals had known they were there and had targeted the location.

There have also been similar thefts in St. Paul and northeast Minneapolis.

In St. Paul, a bonsai tree owner who asked not to be named said tree thieves came into his yard at night twice in August. He said the thieves took 11 potted trees, even though he had tried to secure them.

"As a grown man, I don't believe I've cried like this in front of anyone," he wrote in a Facebook post.

Bonsai tree owners say the costly, miniature trees require constant care.

"If you have them or know where they are, please water them multiple times a day or they will die," Hopkins police said of the trees in the department's news release.

In the Hopkins and St. Paul thefts, security cameras captured photos or videos of the thieves. In the St. Paul theft, three people appeared to be working together to take the trees.

The thefts have put local bonsai tree owners on edge, and many are increasing security at their homes with lights and cameras, said Nicholas Ehlers, a board member of the Minnesota Bonsai Society.

Glassberg said police don't know if the thefts are connected, but "it's a big coincidence."

Bonsai tree hobbyists urge people not to buy trees unless they can verify legitimate ownership.

In the Hopkins case, the owners are offering a $3,000 reward. Anyone with any information can call the Police Department at 952-258-5321.

St. Paul police said information about that case can be reported at 651-291-1111.

Richard Chin • 612-673-1775