When Valentine’s Day arrives, a Plymouth flower-growing business will be at the peak of its popularity.

But Len Busch Roses isn’t popular right now with some of its neighbors, who are raising a stink over the stench coming from wood chips burned to warm greenhouses.

“The last two weeks have been the worse so far,” said Corby Pelto, a longtime resident. “We just want to put an end to it.”

Like most cities, Plymouth doesn’t regulate odor, so the company — the only rose grower in the nation outside of California — isn’t violating any city or state ordinances or pollution rules. And Patrick Busch, the second-generation owner, said wood-burning boilers have heated the 15 acres of greenhouses for the company’s 50 years without any complaints.

“We want to be good neighbors,” Busch said, adding that he lives on the property and hasn’t noticed any odor issues.

“It’s just confusing to us how this emerged. Our process is essentially the same as it has been in the beginning. It’s challenging and unfortunate that this is coming up at this time.”

The Plymouth company has a half-million square feet of greenhouses that produce 7 million stems a year, from lilies to snapdragons and roses, all blossoming in the middle of a subzero Minnesota winter.

The greenhouses are heated by the boilers, which are fed tree trimmings stored in a towering pile in a shelter outside. When the wood chips decompose, they emit the vinegar-like odor.

Busch said the company takes measures, such as cutting the wood chips coarsely, to minimize decomposition, and will now look at other options to reduce decomposition, such as better ventilation.

“It went unnoticed for years and years and years,” he said. “It’s a variable. There is some odor with it, there’s no question about it. But we’re still trying to define the situation. It’s a very, very faint odor.”

The city says that a couple of residents have complained about the odor and the city is working with the company over the unusual complaints.

Pelto, a resident who has lived across the street from the rose grower since 1994, said he started noticing the “decaying” smell last winter.

When the temperatures plunged again this winter, he said the odor returned and he reported it to the city.

“Every winter, we’re having to go through this,” he said. “It doesn’t mean we have to suffer for his business.”

Neighbor Kevin Moody, who also complained to the city, said he’s concerned about the fire hazards of what he said is ever-growing wood piles.

“He has more wood chips than he’ll ever need,” Moody said. “It’s a terrible odor; for a while my wife and I thought something had died. Nobody is monitoring it. There’s no oversight of this whatsoever.”

Busch said most of the neighborhood has been supportive of the company. Now, he’s putting together an odor management plan and looking to reduce the decomposition. There are few other heating alternatives, he added, that are cost-effective for a Minnesota company to continue to grow vibrant flowers in the middle of winter.

“It’s a potential side effect, but it’s part of an environmentally friendly heating system,” he said. “Without that technology, we wouldn’t be able to be in business.”