With cold winters and less than tropical summers most Canadians don't think of planting lemon or olive trees in their backyards. But thanks to global warming, farmer Bob Duncan has been growing a piece of the subtropics on Vancouver Island for 20 years.

Duncan and his wife Verna, who own Fruit Trees and More Nursery, bought their property in North Saanich with the intention of growing fruit trees. While they initially focused on temperate fruits like apples, pears, peaches, cherries and apricots, the couple has had thousands of customers interested in growing lemons and other produce common in the Mediterranean.

"I think it is within reach of every homeowner right now living on the south coast of British Columbia to grow their own citrus and these other types of Mediterranean and subtropical fruits," said Duncan.

According to the nursery owner, it is not the warmer summers that are allowing the growth of Mediterranean and subtropical fruits; rather, it's the milder winters.

He said he's able to grow more types of trees outside of the greenhouse than when he started. The first lemon tree he planted outside nearly 20 years ago now yields several hundred lemons a year, which the Duncans use to make and sell lemon bars, reserving any surplus fruit for personal use.

"The last serious freezes we had here were in the late '80s, early '90s," said Duncan. "Back in the '30s to '60s every few years we would have a cold snap of a week or more duration where the temperatures were minus 10 (Celsius) or worse. You could skate on local ponds and that basically doesn't happen any more."

Duncan said citrus fruits like lemons and limes don't need high summer temperatures; they'll ripen during cooler summers.

"In other words they can be grown outside," said Duncan. "They are still sheltered on a south wall, but they are outside."

Instead of planting trees like lemons and limes in a greenhouse to protect them from colder winters, Duncan uses a cover and a string of Christmas lights.

"The floating row cover allows the sun to pass through, almost like a greenhouse cover, but in a severe cold snap it traps the heat that the Christmas lights give off," he said.

Other than the possible need to offer protection from the cold, Duncan said lemon trees are low maintenance, virtually pest resistant and grow best near a south-facing wall which offers a shield from cold northern winds.

But lemons aren't the only typically warm climate tree becoming popular on B.C.'s south coast.

Michael Pierce of the Saturna Olive Consortium said personal interest from him and some friends was the inspiration to begin importing olive trees from California. Then they realized if they were interested in growing olives, likely others were too.

"We brought in a couple hundred the first year and there was a pretty good response," said Pierce. "The next year we brought in 500, and since then it's been just me doing it."

Although Pierce, whose company is based on Saturna Island in the southern Gulf Islands chain, has found some varieties are more resilient in cold winters, he continues to import others to experiment.

"I'm always testing new varieties and that of course is a long-term thing," he said. "The first year we brought trees in we had a mild winter, and the second we had a harsh winter. It knocked some trees back and in other locations it didn't do anything.

"We've got so many varied microclimates around B.C., which makes it hard to generalize about what varieties grow well."

As with Duncan's lemon trees, Pierce said that anyone interested in planting an olive tree should avoid cold pockets and make use of south ridges or walls for protection.

He doesn't recommend people in places such as the Okanagan or Fraser Valley start growing olives, unless they're able to bring trees inside for the winter. The cold winters in many parts of the country preclude most Canadians from growing olive trees outside.

Because of the cost of an olive press for producing oil, Pierce said he recommends most of those taking the plunge grow fruit for table olives.

"We're talking for a small decent press it's $50,000," he said.

"The problem here with olives is they are going to grow slower, which means to harvest enough to justify the cost of a press, you're going to need quite a few olives."