Wisconsin offers gardeners a choice of six USDA Plant Hardiness Zones. Minimum winter temperatures range from minus-15 degrees Fahrenheit along Lake Michigan to minus-40 degrees in northern Wisconsin. Finding fruit trees hardy enough for Wisconsin's milder winter conditions, however, is reasonably easy. With adequate protection from spring frosts, these trees actually thrive in the Badger State's cool summers.
Forty-six of Wisconsin's 72 counties have commercial apple orchards, according to the Wisconsin Apple Growers Association. After a long period of trial and error, the state's apple growers have learned which trees can tolerate Wisconsin's winters and short growing season. Apple harvest extends from mid-August to late October.
Varieties suitable for both southern and northern Wisconsin include early ripening Lodi, good for pies and sauce, and Jerseymac, an eating apple. Midseason apples are McIntosh, Wisconsin's best-selling apple, and Cortland, another good eating variety. Late-season harvest trees hardy throughout the state are Regent and Empire, with red fruit that ripens in October.
Choose at least two compatible dwarf cultivar trees for your garden, advises the University of Wisconsin Extension. Apple trees need cross-pollination in order to produce fruit. Using dwarf trees from reputable vendors will save space, reduce the risk of disease and ensure an easy harvest.
Pear trees in Wisconsin often lose their fruit crops to spring frost, cautions the University of Wisconsin Extension. A handful of cultivars, however, will tolerate winters in Wisconsin's Zones 4b and 5, in the southern half of the state and along a tiny strip of Bayfield and Douglas Counties on Lake Superior. Plant at least two cultivars to provide cross-pollination.
Look for trees resistant to fire blight and plant them between 200 and 350 square feet for best fruit production. Pick the fruit while still firm and yellowish-green, and ripen it at 50 to 65 degrees Fahrenheit. Suitable pear varieties for both northern and southern Wisconsin include August-harvested Parker, Luscious, Patten and Gourmet.
Tart cherries, says the University of Wisconsin Extension, are stone fruit trees reliable enough to perform in Wisconsin's climate. Choose a variety that doesn't need cross-pollination. Protect or harvest the fruit before birds can eat it. North Star is a small tree and the hardiest of all tart cherries. Its small cherries ripen by mid-July. Meteor's larger fruit ripens about 10 days later.