Bob Osborne is a grower of apple trees in New Brunswick and he has recently published Hardy Apples: Growing Apples in Cold Climates. This book tells you not only all about how apples grow and how you can encourage them, but also talks about over 90 cultivars of apples that are hardy to Zones 2, 3 and 4, which means that most Canadian gardeners will be able to grow at least a few.