Warmer winters have become a fact of life in most of Minnesota, which was confirmed by last week's release of a new USDA Plant Hardiness Zone Map.

But that doesn't mean you can count on a great garden season this spring.

"This has been a weird winter," said Debbie Lonnee of Bailey Nurseries. "It was so dry, with almost no snow cover. Then it was 59 degrees one day, and people were worried about plants budding out."

While it's been relatively mild, the dry fall means plants were already stressed when winter started, and the spare snowfall left them with very little protection against the coldest days.

"Snow is a great insulator," said Jeff Gillman, associate professor of horticulture at the University of Minnesota and author of several gardening books. "Usually we get snow first, then cold." Not this year.

Gillman said he isn't worried about mature, well-established trees, which should weather the winter just fine. But smaller, more marginal shrubs and tender perennials might have a high mortality rate this year.

Even gardeners who have had past success creating microclimates may be disappointed this spring, he said. "This is the kind of winter that out-duels a microclimate."