Apple Tree Guide
This is an Excerpt from the Book called “The Backyard Orchardist” by Stella Otto. Continue reading to leran more about Apple Tree Guide, thanks to the author.
Apples
The apple is the tree fruit most widely adapted to growing in backyard orchards throughout the country. It has many varieties to choose from and is one of the most popular eating fruits.
Growth Habit
Let us look at the overall apple tree first. Normally the apple tree grows in a certain manner. The term “growth habit” is used to express the typical way and shape in which a given variety of tree grows. An apple tree, as it grows up and out, develops what is called a central leader habit. It has one main growth shoot that tends to dominate and grow straight up, becoming the trunk. Numerous side branches, also known as laterals, will radiate out from the trunk and form the overall scaffold or general skeleton of the tree. These will be the layers of horizontal branches that continue to grow outward and form additional layers of branches as the tree grows taller. Within the central leader growth habit of the apple, some varieties such as Red Delicious, Northern Spy, and Paulared, tend to grow very upright. Other varieties such as Cortland, McIntosh, and Empire tend to grow with more horizontally oriented laterals. Yet others, such as Rome, have flexible, long, slender branches that are rather willowy in their growth. The illustration on the previous page shows some of the growth habit variations you might encounter, all still within the central leader training system.
Flowering and Fruiting
Just as the apple tree has a certain habits of growing, it also has a certain way in which it produces its flower buds. Every type of fruiting tree must produce some buds that will produce new branches (or vegetative growth) and some buds that produce blossoms (and consequently fruit). Some types of fruit trees produce all of their flowering buds on wood that was produced during the preceding growing season, or said another way, on last year’s wood. Other types of trees produce flower buds on wood that is several seasons old and some produce flower buds on short, modified branches called spurs.
On apple trees most of the blossoms are borne on fruiting spurs. These spurs are generally short, compact growing branches less than four inches long. Most commonly, one year they will bear a fruit bud (or flower bud, the terms are used inter-changeably) as their terminal bud. The following year a vegetative bud will be produced at the spur terminal but growth will be short and compact. Production of fruiting buds and vegetative buds will alternate in subsequent years. This alternation of fruit and vegetative production will give the spur a zigzag appearance to its growth as shown to the left. Of course, not all spurs are producing vegetative buds in the same year so there is normally an adequate supply of fruit buds to keep a crop growing every season
Another factor to keep in mind is that, although it is not visible to you, the apple tree is already developing its fruit buds deep within its tissue the summer prior to the year in which the bloom becomes visible. Starting in about mid-June, the fruit bud tissue starts its development and differentiation. The process is completed by late March, shortly before bloom. Several factors, including the amount of light, water, and nutrients available can affect the development of the bud.
The production of flower buds alone is not enough to ensure production of a successful apple crop. It is really only the first step. Once the bloom is visible, the important processes of pollination and fertilization are also going on. Pollination is the transfer of pollen from the male parts of a flower blossom to the female parts. Fertilization occurs when the male and female genetic material are united to form an embryo which can then develop into the fruit. Both of these processes are discussed in detail.
To complicate matters, though, a number of different fruit varieties have pollen that is not compatible with itself. This is the case with apples. Most apple varieties need to be pollinated with pollen from a different apple variety. As an example, a Red Delicious apple with not produce much fruit successfully if pollinated by another Red Delicious. This condition is known as being self unfruitful. However, if that same Red Delicious blossom receives pollen from a McIntosh bloom, it will most likely develop a nice crop of fruit (other normal conditions cooperating). This process of sharing pollen between varieties is known as cross pollination. Some readers may wonder what apple variety will result from this cross pollination. The fruit variety will always be determined by the blossom variety, as it is the tissue of the female parts that develops and expands to from the fruit. You could view it as the fruit always origination from the blooming “mother” tree regardless of which other tree provided that pollen. If the blossom of a McIntosh tree has been pollinated, the fruit will be McIntosh. So, when planting apple trees it is advisable to plant at least two varieties to facilitate cross pollination.
| Relative Bloom Time of Some Popular Apple varieties | |||
|---|---|---|---|
Early | Midseason | Late | |
Idared | R.I Greening | Jonafree | Honeycrisp |
Paulered | Priscilla | Akane | Fuji |
Mclntosh | Cortland | Granny Smith | Braeburn |
Wealthy | Empire | Prima | Macoun |
Jonamac | Winesap | Jonathan | York |
Spartan | Regent | Gala | N.Spy |
Liberty | Red Haralson | Honeygold | Rome |
Gravenstein | Arkansas Black | G.Delicious | |
Jerseymac | Red Delicious | Jonagold | |
Mutsu | |||
It is also important to pay attention to when the various varieties bloom, because the time that the blossom of one variety is open needs to coincide closely with the time that the pollinating variety is also blooming and providing the needed pollen. Some popular varieties that normally bloom together are found on the previous page.
It is best to choose two or more varieties from within the same blossom time group, but it is possible to choose one variety from the early group and one from the middle blooming group as their bloom time will often overlap somewhat. If you choose one variety from the early group and one from the late, however, their bloom times will likely be too far apart to pollinate each other well.
There is also a small group of apple varieties that, due to quirks of nature, have a triploid number of chromosomes. As a result, their pollen is sterile. Although that can be successfully pollinated by other varieties, they cannot themselves serve as reliable pollen sources. If you do want the fruit from one of the varieties listed below, be sure that your fruit planting is made up of at least there apple varieties, including those with viable pollen.
Need for Thinning
As discussed in more detail, many fruit tend to produce far more blossoms than are needed to provide a full crop. In fact, if all properly fertilized blossoms are allowed to develop into fruit, the result will be an excessive crop of small, marginally usable fruit. Nature usually takes care of thinning some of this excess in the “June drop.” Often additional fruit lets need to be removed by hand thinning. This is the case for apples. The insecticide carbaryl (Sevin@) will also thin apple and pear fruit when used within 30 days of bloom, so consider this in the management of your trees.
Research has shown that it takes about 30 healthy leaves on spur type varieties and between 40 to 75 leaves on standard, nonspur type varieties to produce each large, well colored apple. Early maturing varieties typically require the higher leaf to fruit ratio.
When hand thinning try to keep the largest fruit, which has usually resulted from the king bloom. Space fruit about 4 to 6 inches apart on the branch. For spur bearing varieties, ideally fruit should be thinned to at least every other spur.
Some varieties, notably Gala, Liberty, and Macoun, will set large crops with multiple fruit on each spur. To avoid fruit crowding and small fruit at harvest, it is critical that these varieties receive proper thinning down to a single fruit per spur. Varieties that have a propensity for biennial bearing, such as Cortland, Fuji, Golden Delicious, Golden Supreme, Granny Smith, Gravenstein, Haralson, Honeycrisp, Jonagold, Mutsu (aka Crispin), Rhode Island Greening, Spy, and Spygold are more likely to produce annual crops if well thinned.