ST. STEPHEN, New Brunswick – A couple’s green thumb has received a stamp of approval from the U.S. Department of Agriculture.

For years, Peter and Norah Heelis have run Mayfield Greenhouses with about 20 employees across the border from Calais, Maine. And for years gardeners across the border were part of their customer base.

But about a year ago, the U.S. Department of Agriculture told Mayfield that it needed to comply with some regulations about plant diseases and pests, and the USDA announced a crackdown on plants being brought into the United States. The couple learned that they could not legally sell to U.S. customers without those customers jumping through a series of hoops, including paying a fee to take their plants across the border.

That led to months of work and their participation in a U.S.-Canada-approved certification program.

“It’s a program called the Canadian greenhouse certification program, and what it means is our whole facility had to be certified,” Norah Heelis said. The program allows Canadians to export greenhouse-grown plants to anywhere in the United States.

The business had to undergo an inspection and is subject to monthly inspections by the Canadian Food Inspection Agency. USDA also can inspect Mayfield at any time. Heelis said she and her husband already had in place good greenhouse practices and that the program made them formalize some of those practices. “There wasn’t much of a change for us because we’ve always done pest management, which means monitoring for pests, and keeping good records of any problems we ever had,” she said.

Americans who go in search of the Canadian garden plants have to do very little. They simply have to declare they are taking the product across the border and a sales clerk can fill out a form. At the border, the customer declares the purchase and shows the form.

Heelis said some shrubs and nongreenhouse plants do require a phytosanitary certificate, which guarantees that the plants are free of disease. A Canadian agriculture inspector certifies that the plants are bug-free. The cost is $15 Canadian.