H327 (Revised) Tree Fruit Culture and Cultivars in North Dakota Revised by Moving west and north across the state, conditions become less favorable Tom Kalb for growing fruits because of extreme temperatures and reduced rainfall. Horticulturist However, with proper selection and the necessary cultural practices, NDSU Extension Service the home gardener can harvest ample fruit most seasons. Protecting fruit trees from harsh winds in winter and summer cannot Growing your own fruit be overemphasized. City dwellers usually have a more favorable environment for establishing fruit trees than rural residents because the can be fascinating and fun. concentration of buildings and shade trees can greatly reduce wind velocity. Many different kinds of tree On farms, the fruit tree planting is best located within the building site. fruits, including apple, pear, Wind protection may be provided by hills, buildings or shelterbelts. plum and cherry, can be Shelter is necessary from all directions except the east. grown successfully in Fruit trees should be planted at least 40 to 50 feet from farm shelterbelts North Dakota. to prevent breakage from snowdrifts and reduce competition between the fruit trees and shelterbelts for sunlight, soil moisture and nutrients. In town, where backyard space may be limited, locate fruit trees away from large shade trees for similar reasons. Most fruits do well on any fertile garden soil that has good surface drainage. July 2016 1 • H327 Tree Fruit Culture and Cultivars in North Dakota How to Select Cultivars Well-branched trees can be developed Gardeners in northern areas will by the homeowner even if only a Fruit Tree benefit from choosing the most healthy, unbranched trees between 5 and 6 feet tall are available. A consumer visiting a local nursery hardy and earliest-ripening cultivars. After planting and before the buds often is overwhelmed with the See Pages 5-7 for a complete listing and break, the tree can be cut about selection available. Choosing a good description of recommended cultivars. 36 inches above the graft union. tree from the inventory is not as simple Cultivars are listed in order of ripening. A healthy tree will respond with as you might think. Following certain several branches developing below criteria will help make a good selection. Tree Size the cut, allowing the homeowner They are hardiness, tree size, branch Look for trees that are at least ½ inch to make selective cuts later on number, branch angle and, to help in diameter just above the graft union. for good branch distribution. get the properly selected tree off Experience has shown that trees to a good start, planting time. smaller than this do not establish as well as larger ones. However, Branch Angle Hardiness bigger is not always better! If a tree Wide-angle branches (60 degrees from the central axis of the tree) Hardiness is the most critical factor is allowed to get too large (1-inch will be the strongest. Vigorous, when selecting varieties for North diameter or more) at a nursery, a upright branches – often called water Dakota. The U.S. Department of significant part of the root system may sprouts – will not be contributors to the Agriculture’s Hardiness Zone Map be damaged or removed in digging. overall production and strength of the (Figure 1) is based on extreme winter This will give an unbalanced ratio tree. Branches that are at a wider or temperatures. Most North Dakotans between the top and root system flatter angle will produce fruit earlier live in Zone 4a (minimum winter of the tree, creating problems in than sharp-angled branches. Overall, temperature of minus 25 to minus establishment and survival. the tree should have a pyramidal shape 30 F). Consider this map as a guide, to make efficient use of the sunlight. not a hard and fast rule. Exposure to Branch Number wind, alkalinity and soil moisture also Ideally, a tree should have three to can affect the adaptability of a variety. five symmetrically spaced branches that Planting Time Asian pear, sweet cherry and peach are about 4 to 6 inches apart starting The urge for spring planting is are not reliably hardy. about 2 feet above the graft union. overwhelming in North Dakota. You can meet this desire easily by planting bare-root stock as soon as the frost is out of the ground. Experience has shown that bare-root planted trees, if healthy, will exhibit vigorous growth and establishment the first year. Some nurseries order bare-root stock to offer to early shoppers, then pot the remainder for sale throughout the growing season. The fall planting season often is overlooked. At that time, the trees are moving and storing carbohydrates in their root systems. Consequently, no visibly active growth is witnessed above ground. All the action is taking place in the roots, which continues until the soil temperature reaches about 40 F. Fall-planted trees often will exhibit greater vigor the following spring than spring-planted ones in comparable situations. Figure 1. Hardiness zone map of North Dakota. 2 • H327 Tree Fruit Culture and Cultivars in North Dakota Dwarf Apple Rootstocks Pollination Tamp firmly. Leave a depression Dwarf trees are smaller than standard Many tree fruit cultivars cannot set around the tree and water thoroughly. trees because of the influence of the fruit with their own pollen, so you The lowest branch should be located rootstock on which they are grafted. must select and plant two different on the southwest side of the tree to Dwarf trees bear crops a few years cultivars to ensure fertilization. reduce sunscald problems. earlier than trees grown on standard Apple, crabapple, pear, American rootstocks. They are easier to prune, plum, apricot and cherry plum will Pruning spray and harvest. They can be incorpo- set more fruit if two or more cultivars Minimal pruning is done at planting. rated into nearly any home landscape. are present. Pie cherry and European For branched trees, remove broken blue plum cultivars are self-fruitful branches. If branches are rubbing The hardiness of apple rootstocks and can set fruit on their own. against one another, trim out the least limits their use to Zone 4 in North desirable branch. The tree may be Dakota. Sheltered sites with expected trimmed back to 1 foot above its snowfall are best. Spacing Apple trees should be spaced for easy tallest side branch, making sure the Budagovsky 9 (Bud.9) is the hardiest cultivation and full tree development. top of the “central leader” remains rootstock and will grow trees up to 10 For trees on standard rootstocks, the highest point of the tree. feet tall. It resists fire blight. The root- minimum spacing is 20 by 20 feet and For nonbranched “whip” trees, stock M.9 is one of the most common preferably 25 by 25 feet. Semidwarf cut the trunk at 30 to 36 inches. dwarf rootstocks used in the U.S., but it trees can be spaced approximately This will stimulate the first flush is susceptible to fire blight and is only 15 feet apart and fully dwarf trees of scaffold branches at that point. marginally hardy. The hardiest of the approximately 8 to 10 feet apart. East Malling series of rootstocks, M.26, A young tree needs little pruning Plum, cherry and apricot trees will grow a semidwarf tree, but it is except to select proper main branches. should be spaced 10 to 15 feet apart. susceptible to fire blight. All of these The first branch should begin about Cherry plum trees should be spaced rootstocks need to be staked. 30 inches from the ground. 4 to 8 feet apart. The most popular dwarfing rootstock, In the next 24 inches, develop the M.7, is not quite as hardy, but it is first series of major scaffold branches used in many Zone 4 orchards. It will Caring for (Figure 2, Page 4). Four branches, develop into a semidwarf tree that one each facing a different direction grows 12 to 15 feet tall. It is grown as a a Fruit Tree (north, east, south and west), is ideal. free-standing tree except in windy sites. These branches coming out of the Planting trunk should resemble spokes Dwarf apple trees are planted so the You can plant dormant bare-root fruit coming out of a wagon wheel. graft union is at least 2 inches above trees early in the spring, while you can the ground. This will prevent the plant potted nursery stock throughout Maintain a 24-inch gap between this upper portion of the graft (scion) from the growing season. group of scaffold branches and the next. establishing roots that will reduce the This will maximize sunlight and air When planting bare-root trees, dig a dwarfing effect of the rootstock. movement between the sets of scaffold hole larger than the root spread of the branches. As the tree grows, another A 10-foot-long, ¾-inch electrical tree to avoid crowding or bending the 24-inch gap, followed by third set of conduit pipe is the most common roots. Take care when planting potted scaffold branches, is developed. staking material. Pound the stake trees that are growing and in full leaf 2 feet deep into the ground a few to prevent the loss of soil around the When the tree reaches fruiting age, inches from the tree. roots when removing the container. annual pruning will help maintain Always remove containers before a healthy, well-structured tree and Many nurseries in North Dakota planting. Do not place soil amendments encourage annual bearing. On all fruit sell apple trees grafted onto ‘Dolgo‘ and fertilizer in the planting hole. trees, prune all suckers that originate crabapple rootstock.