GROWING AN APPLE TREE

An apple is a sweet, edible fruit produced by an apple tree (Malus pumila). Apple trees are grown worldwide and have been cultivated by humans for thousands of years.

There are over 7,000 varieties of apples grown for reasons as wide ranging as fresh eating to cider making, so it is important to choose one that is right for your area and needs. Apple trees became popular in the 17th century after being imported to America by early settlers due to their versatility, ease of preservation, and the high value of apple cider. By the mid-1800s apple fruits, especially cider apples, would become the most common fruit grown in America.

Apple cider remained extremely valuable until the prohibition era of the 1920s and 1930s that outlawed all forms of alcoholic beverages, leading to the removal of the majority of America's older cider apple orchards. Modern day apples are no less popular however and thanks to fruit historians, and avid enthusiast, many of our old heritage varieties are making a come back!

Choosing a Variety

Type

Centuries of cultivation and selection have given us a wide variety of apples, both large and small, for many different uses. Different apple tree varieties have different pollination requirements and the fruits have a wide range of textures and uses in your kitchen including fresh eating, jam making, drying, baking, sauces, salsas, chutneys, vinegars, and making alcoholic beverages. Many apples are "dual-purpose", meaning they Below is a brief list of the different types of apple trees you can plant and cultivate in your own orchard.

FRESH EATING

Many modern apples found commonly stocked in supermarkets and at fruit stands are considered fresh eating apples, prized for their texture, flavor, color, and aroma - all factors that come together to create a the transcendent experience of biting into a fresh apple. Many fresh eating apples are also prized for their self life, allowing for long periods of storing and shipping. Some fresh eating apples are meant to be eaten as soon they are ripe, while others are best eaten after a period of a month or longer in storage. Classic fresh eating apples include Honeycrisp, Cherry Cox, and Williams' Pride, and Akane apples.

Cooking - Cooking apples are found more commonly in Europe than in the United States, where they are still grown commercially and held in great esteem for their intense flavor and texture during and after the cooking process. Cooking apples are typically much more sour, bordering on astringent, and when cooked with a sweetener hold onto their "apple" flavor far better than fresh eating apples. Classic cooking apples include Bramley's Seedling, Wynooche Early, King Edward VII, and Enterprise.

Cidering - Cidering apples have unique flavor profiles, typically high in acid and tannins, that make them most valuable once pressed and fermented into apple cider. Some cider apples can be used to create "single variety" ciders, while others are best used as part of a mixture of cider apple varieties. The practice of cider making has experienced a resurgence in recent years, making it possible to bring back traditional cidering varieties that were nearly lost due to the destruction of many cidering orchards following prohibition. Classic varieties including Dabinett, Harrison, and Medaille D'Or are becoming more and more common in home orchards and even commercial orchards.

Crabapples - Crabapples are the workhorses of the orchard. Due to their natural disease resistance and longer than average blooming period, crabapple varieties have long been used as reliable pollinizers for many different kinds of apples. In addition to their value as pollination vectors and pollinator forage, crabapples were bred for their value as flavor components in apple cider. The most famous, and widely planted, crabapple was Hewe's Virginia, which could be found throughout the whole of the early American settlements. Today crabapples, such as Evereste, are planted for their incredible floral displays, while others like Dolgo have been bred for size and flavor.

SIZE

Size is an important consideration when choosing an apple tree. Apple trees can be narrow or spreading, very tall to 50’ or very manageable at 6-10’, and can be grown in containers, as landscape feature plants, or in an orchard. Modern apple trees are grafted to specific rootstocks that naturally control their size and provide additional resistance to common pests and diseases the grafted cultivar may not have the ability to defend against.

Take a look at this size chart showing apple trees grown on different rootstocks.

Pollination

Unless otherwise noted, all apples need another variety of apple nearby to cross pollinate each other. Using the apple pollination chart below to determine which pollinizer tree variety is the right choice will help ensure your orchard will be successful and productive. Apples in the same and adjacent flower groups will reliably pollinize each other.

Example 1: Honeycrisp is a mid-late season blooming apple. It can reliably cross pollinate with apples in the mid-season, mid-late season, and late season. It cannot cross pollinate reliably with trees in the early season and early-mid season.

The pollinizers should be planted no further than pollen carrying bees will fly, with no line of sight obstruction, to ensure proper cross-pollination. That distance varies with different bees, 100’ should be a good average distance.

TRIPLOIDS

Some apple trees are triploids, which have three chromosomes instead of two, and in turn are functionally pollen sterile. Triploid trees still need cross pollination to create fruit, but do not provide compatible pollen to pollinize other nearby trees. When including a triploid cultivar in your orchard make sure that the other trees in your design will be able to serve as pollinizers for each other in addition to the triploid.

Common varieties of triploid apples are Gravenstein, Jonagold, Thompson's Kind, and Ashmead's Kernel. Triploids are listed in red text on our apple pollination chart.

SELF-FERTILITY IN APPLE TREES

Self-fertile apple trees, trees that make compatible pollen for their own female flowers, are uncommon in apple trees, but do exist. Depending on your location a tree's self fertility may vary or even change from one region to another. Where we are based in the Pacific Northwest only the Queen Cox apple is considered reliably self fertile.

Cultivars that are not self fertile here may be partially or completely self-fertile in other parts of the United States. We cannot accurately answer any questions you may have about which of the apple varieties we carry may be self-fertile in your area. Please contact your local extension service for more information on your specific growing region.

Ripening Time

Apple tree fruit generally ripen from mid-summer through late fall, depending on the variety and your location. As you make your selections double check that pollination needs are also met as early-flowering trees does not necessarily mean early-ripening fruit. Apples that ripen early tend not to store well and do not last long on the tree, where as later ripening varieties tend to have longer storage times and remain edible on the tree longer.

Generally speaking your apple tree fruit are ready to pick when apples begin falling from the tree. Some varieties come off the tree easily when ripe, while others do not. Some types of apple are meant to be picked early and allowed to mature in storage and some, like Gravenstein may ripen unevenly and need to be picked over a period of weeks.

USDA Hardiness Zone

Unless otherwise listed, apple trees are hardy to USDA zones 4-9, making it possible to grow them all over the United States! The USDA zone rating tells you the minimum winter temperature at which the plants typically survive when properly hardened off. On the USDA website you will find a USDA Hardiness Map which provides information on the average minimum winter temperature in your location, by zip code.

It should be understood that a USDA zone only refers to winter low temperatures and not the overall growing conditions for your area, such as rainfall, summertime temperatures, season length, soil quality, chill hours, or any other factors that go into successfully growing your apple trees.

Chill Hours

To regulate hormones and produce healthy flowers and fruits all plants must undergo a period of dormancy. Dormancy, which is like a kind of sleep for plants, is triggered by what we call "chill hours" or "chilling hours" - a period of time where the temperature is between 32 and 45 degrees Fahrenheit. Different varieties of apples will require different amounts of chill hours, with cultivars requiring less than 600 hours being considered "low-chill".

Most apples have a standard-to-high chill hour requirements at 600-1000+ for most varieties, with a few exceptions.

If you have questions about the chill hours in your area contact your county Agriculture Extension Office to get your local details!

Where to Plant Your Tree

Apple trees need to be planted where they receive at least 6-8 hours of direct sunlight as measured in early summer (late June to early August). Sufficient sun exposure triggers the initiation of new flower buds for the next growing season, without which there will be no fruit. Fruit ripening and flavor development are also benefited by the carbohydrate production stimulated by the sun, as well as the sun's heat.

Apple trees tolerate a wide variety of soils, but a well-drained sandy loam soil at a pH of 6.5 is ideal for growing apples. Improve your soil where you intend to plant by mixing an inch or two of composted organic matter, aged manure, or leaf mould into an area 2 times the diameter of the planting hole and up to a foot deep. A 2-4” deep layer of mulch (straw, leaves, or wood chips) applied after planting will continue to improve the soil and maintain moisture.

Allow sufficient space for both the top of the apple tree and its root system when selecting the planting location. Refer to size descriptions for each variety, keeping in mind these are generally managed or pruned sizes, not maximum potential sizes. If you are planting an orchard be sure to include enough space between rows for healthy airflow and for transporting your supplies in and your fruit out.

Growing in Containers

Columnar apple trees and mini-dwarf grafted apple trees are the best candidates for growing an apple tree in a container. Dwarf grafted apple trees can also be grown in a container with annual pruning and occasional root pruning. Be aware that pots are a very different environment than planting a tree in the ground. Due to their nature pots typically have higher soil temperatures, lower soil moisture, lower water holding capacity, and limited fertility. Growing an apple tree in a container will require careful attention to location, irrigation, and require more frequent fertilization to be successful over time.

One of the benefits of growing apple trees in containers is the ability to grow apples in conditions you may not normally be able to plant trees in. Container growing is a great solution for enthusiasts that may not have access to a permanent orchard space, adverse soil conditions, live in an urban environment, or want to grow several cultivars without having to worry about excessive fruit production and ladder work during harvest and annual seasonal pruning.

To grow an apple tree in a pot you need a final container size of at least 25 gallons. Trees will grow larger in a larger container, but make sure you have the ability and tools to move the pot's heavy weight.

Do not use soil from your garden in the pot, instead use a potting soil mix with some added compost. For larger pots use a potting mix that has larger particles in addition to the smaller ones.

Care and Maintenance

Watering Your Tree

This is the most important and often the most difficult part of successfully growing plants. There are many factors, including the humidity, temperature, soil type, wind, and amount of direct sun that affect how much and how often water should be applied.

A general rule of thumb for plants in the ground is to ensure they receive an inch of water per week over the root zone. An inch of water is equivalent to about ¾ to one gallon per square foot of soil surface area. The typical three foot diameter planting hole would need 7 ½ to 10 gallons of water per week provided by rainfall and/or by the gardener.

Apply this water once a week, two times per week if soil is fast draining.This will of course depend on your own conditions and the plants you are growing! Do NOT water lightly each day because this results in a wet surface and dry root zone area. The soil should be moist but not soggy to a depth of about a foot for most growing plants. The top inch or two can feel dry, and the plant still b well watered. The trick is to have the water available where the roots are. In hotter and sunnier areas, a mulch of straw, bark, etc. can greatly ease the burden of summer watering.

For plants in containers,water until the soil is saturated and water comes out of the drainage holes. Let the container dry until the soil is dry to the touch 1-2inches down (more deep with deeper pots) and the container is lighter in weight. A plant that has wilted can be receiving either too much or too little water.

In rainy areas like the Pacific Northwest most of the plants that we offer will need relatively little supplemental irrigation ONCE THEY ARE WELL ESTABLISHED in the ground and have had a chance to develop a good root system. However even here it is important to make sure plants have regular, deep watering during the first couple of growing seasons, and the first summer is especially critical. In drier areas, or where soils do not retain water well, permanent irrigation is required. Remember that you don’t want your trees to just survive, but rather to thrive. Make sure they get the water where they need it, starting at the drip line and extending away from the tree several feet (for older trees) where the feeder roots will be.

FERTILIZATION

For good steady growth and high productivity, your trees need to have adequate amounts of various mineral nutrients. Some people are fortunate and have naturally rich fertile soil. Many soils, however, are deficient in some nutrient or another and use of fertilizers, organic or chemical, can be highly beneficial if you want your trees to grow well.

Vertical splits in bark appear spring or early summer, usually on the south or east side of the tree. Disease or insect infestations may then occur.

CONTROL METHODS

Whitewash trunk and lower limbs with interior latex paint cut 50/50 with water each fall until bark has thickened. Avoid planting in frost pockets or where water collects in winter.

Comments

Injury occurs during pattern of warm days followed by freezing nights. Sap gets stuck in trunk, freezes, then rapidly thaws in the warm sun the next day, rupturing cells.