The apple tree (Malus domestica) is an extremely adaptable plant that can thrive in a myriad of sites throughout the temperate regions of the world. Originating in the mountains of Kazakhstan, its domestication dates back thousands of years and has since spread throughout the world. Brought to the Americas in the 17th century by European colonists, the apple has been a mainstay of American culture and its impact on Arizona is no different. Today, thousands of apple cultivars exist and many of them are available for sale in nurseries throughout the United States. With so many choices, it can be a challenge to know which varieties are appropriate for any given region, let alone site. This publication aims to serve as a guide for people living in the Arizona Central Highlands (the transitional zone that acts as a demarcation between the Basin and Range of southern Arizona and the Colorado Plateau of Northern), drawing on real world experience and recommendations of growers living there.
While specifics were often limited to available data for each cultivar, information is conveyed using the following seven categories, which are intended to help (primarily backyard) growers select the proper apple variety.
- Historical context includes parentage, origin, and year of introduction to the public.
- Fruit characteristics often including appearance of skin and flesh, texture and flavor.
- Uses such as fresh-eating, culinary, cider-making, and refrigerated storage capabilities.
- Fruitfulness including precocity (time to fruit production from juvenile to mature), crop size, propensity to alternate bear (produce a large crop one year, and a significantly smaller one in the next), and pollenizer requirements (it is almost always beneficial to have a second tree, even if the variety is self-fruitful.
- Phenology or key developmental timings such as bloom, ripening, and harvest. These are moderated by site (warmer sites will speed up ripening) and crop load (higher crop loads will slow ripening).
- General tree characteristics such as size, architecture, and disease resistance. Most trees bear fruit on shortened shoots called spurs; if partially or completely tip-bearing (sets fruit at the ends of last year’s shoots), it will be noted.
- Site selection using USDA Hardiness Zone, general temperature preferences and “chill hours."
The USDA Plant Hardiness Zone map (updated in 2023) was created as a way of conveying the average minimum annual temperatures to growers and gardeners of perennial plants such as fruit trees and landscape plants. The concept of “chill hours” is used to describe the number of hours between 32- and 45-degrees Fahrenheit that a perennial plant must experience during the dormant season in order to ensure uniform budbreak and bloom. Varieties that have relatively low chill hour requirements planted in colder climates will start breaking bud too early and are likely to lose blossoms due to frost or endure regular, destructive, cold events that could eventually kill the tree. A disclaimer should be noted: these values are generally considered 'ballpark,' but they are useful in deciding whether a particular variety is a good choice for a specific site.
This publication focuses on scion varieties—the fruit-bearing upper parts of trees that are grafted onto rootstocks. Although rootstock selection is not a primary focus here, nurseries consulted strongly recommended, and most likely sold, MM-111. This semi-dwarfing rootstock confers several desirable traits, including moderate size control (trees typically reach 16–20 feet), precocity (earlier fruiting), tolerance to alkaline soils, and resistance to woolly apple aphid.
In all, 37 varieties were selected from a larger pool that was recommended by local experts, filtered for inclusion based on their availability to consumers. A great deal of thanks is given to Sandra Lockwood.