Many people assume that because Colorado is a high altitude environment, fruit trees don't grow well in the state. Colorado's environment, however, is ideal for a number of fruit trees. The majority of the state on either side of the Rocky Mountains is USDA Hardiness Zone 5.
Peaches grow well in many parts of Colorado. Although peaches are sometimes considered less reliable than other fruits because of the risk of flower damage by late spring frosts, with proper planting and care many varieties of peaches will grow well in Colorado. When planting peaches in Colorado, avoid low lying areas that can be susceptible to late spring frosts. Make sure your trees get full sun and grow in soil that drains well. Varieties recommended by Colorado State University for the state include Elberta, Haven, Polly, Reliance, Hale Haven and Ranger.
Colorado is ideal for many varieties of apple trees. Colorado's climate on the plains provides an adequate cold period for most varieties of apple. Apples require a cold period for the fruit to set in the spring. In some cases, apples will grow part way up the Rocky Mountains. According to the Denver Post, some varieties of apples can grow up to 8,000 feet in USDA Climate Zone 4. To grow apples in Colorado, select varieties that ripen by early October to avoid early frost fruit damage. Varieties that do well in Colorado include Golden and Red Delicious, MacIntosh, Gala, Granny Smith, Honeycrisp, Cortland, Fireside, Haralson, Jonathan, Cox Orange, Northwest Greening, Joyce, Wealthy and Lodi.
Although cherries can grow well on the eastern and western slope of the Rocky Mountains, unpredictable weather on the eastern slope, often called the Front Range, makes growing cherries risky. Colorado cherries grow best on the western slope of the Rocky Mountains. Cherries commonly grown on the western slope include Bing, Rainier, and Queen Anne cherries. Many Colorado cherry orchards mix other fruits with the cherry trees, including peaches and apricots.