Peach is the least hardy of the family of stone fruits that includes apricot, cherry and plum. Winter cold and late spring frosts can easily kill buds and flowers or crack twigs and trunk bark. Peaches are best grown in southern Wisconsin, which sits in USDA plant hardiness Zone 5. Zone 4 areas toward the middle of the state are possible, but problematic. The University of Wisconsin recommends researching the most winter-hardy cultivars, and recommends only three for planting in Wisconsin.
Reliance peach trees are the hardiest available, and rated for Zones 4 to 8. They are the latest blooming, and have the best chance of surviving spring frosts in Wisconsin. Their fruit is golden-skinned with a red blush. The flesh inside is yellow and juicy, the stone doesn't cling, and it ripens in June or July. Like all peach trees, Reliance is self-pollinating, so you don't have to plant a different cultivar or more than one tree to get a crop.
Try Harrow Beauty peach trees for their disease resistance and smaller, more compact shape. According to Ontario's Ministry of Agriculture, Harrow Beauty produces a firm, medium-sized peach, and the stone inside is outlined with an attractive red band of flesh. Not quite as hardy as Reliance, these trees should be planted in some shelter, such as a gentle, southeastern slope, where cold air can drain down and away.
Plant Madison peach trees for a large, midseason crop of peaches, but be alert to pests and diseases like brown rot, scab or peach tree borers. This tree is highly productive early in life, and begins to bear fruit at the age of three or four. Give Madison plenty of room, spacing trees at least 25 feet apart. Fruit is medium-sized and tasty, golden-skinned with a high, red flush.