Don't zone out. While he tries plenty of unusual plants -- including kiwi and Meyer lemon, both of which he overwinters inside -- Campbell relies primarily on plants that are hardy in USDA zone 4. "I'm zone-sensitive," he said. "I've lost too many plants to fall for zone 5 plants anymore."

Shop around. To find the "oddball" plants he loves, Campbell shops around. He gets lots of garden catalogs, but he also shops at local farmers markets, garden centers and nurseries. One of his favorites is Savory's Gardens in Edina (, which specializes in hostas.

Make good use of the off season. When the gardening season is done, Campbell not only tends to the dozens of plants he overwinters inside, but also researches new plants he might want to buy next spring.

Know your limits. While he'll make an extra effort for certain plants ("I want it on my gravestone that I produced kaffir limes"), he would never fill his garden with high-maintenance plants. "I love the stuff that just grows and takes care of itself," he said. CONNIE NELSON