How to choose and grow columnar fruit trees
Everything you need to know about growing columnar fruit trees, including care and selection of species and varieties
Columnar fruit trees are very popular among growers and there are several reasons for this. This type of tree allows people who don't have a large yard to grow fruit. Columnar fruit trees can even be grown in pots so that they can be placed on balconies and terraces, making them great for urban growers.
But their benefits don't stop there. Thanks to their shape, columnar fruit trees can be planted with smaller spacing to create a natural partition in the garden, a kind of edible hedge, in gardens of any size. In this way it is possible to grow several varieties in a smaller area with a very good yield, and the columnar shape of these small trees also allows good access, which results in convenient care and harvesting of the fruit.
What are columnar fruit trees?
Simply put, these are fruit trees grown in a columnar form, without long lateral branches. Columnar fruit trees usually only grow to 6-10 feet (2-3 m), which is either a genetic trait or due to being grown on dwarfing rootstocks. There are two general types of columnar fruit trees:
1. True columnar varieties of fruit trees - specially bred varieties with natural columnar growth that does not need to be substantially shaped
2. Classic fruit tree varieties grown on dwarfing rootstocks, formed into a columnar shape with regular pruning
Columnar fruit tree varieties
1. True columnar varieties of fruit trees
The true columnar fruit trees, specifically bred for this purpose, are exclusively apple varieties. The first columnar apple varieties were bred in the second half of the twentieth century from a natural mutation of the McIntosh variety (Wijcik McIntosh) discovered in Canada, which was unique for its unusually short lateral branches and short upright stature. Crossings of this mutant with several other varieties gave rise to the first columnar apple tree varieties, also called ballerinas (the charlotte, flamenco, samba, waltz, bolero and polka varieties). Varieties of the ballerina series quickly became popular because they were fruitful, required almost no maintenance and had an attractive new growing shape. However, ballerina varieties also have some weaknesses, particularly their susceptibility to disease and less intense fruit flavor.
Modern columnar apple varieties are now more resistant to diseases such as scab and powdery mildew. They also produce fruit with full, intense flavor and are available in a greater number of types and varieties. The best known true columnar apple varieties include Sonet, Rondo, Kordona, Northpole, Maypole, Pompink, Pomfital, Pomgold, Pomredrobust, Pomforyou, Starcats, Goldcats, Greencats, Redcats, Redcats, Suncats, Red sensation, Vasiugan, Golden Sentinel, Scarlet Sentinel, Arbat, Valiuta, Gatis, Nataliuska and many others. True columnar apple trees require almost no maintenance and can be grafted on both dwarfing and medium rootstocks (MM111, MM106, G969, G935), which gives them greater stability, strength and, above all, longer life (they reach the full productive life of standard apple trees grown on vegetative rootstocks: 30 - 50 years).
When selecting columnar fruit tree varieties, be aware that sellers often label apple varieties as columnar even when they are certainly not true columnar varieties. It is common to see ‘columnar’ varieties such as golden delicious, gala, jonagold or other popular apple varieties, but in reality these are just classic varieties grown on dwarfing rootstocks and pruned into a columnar shape. Unlike true columnar apple trees, these varieties will require annual pruning to maintain their columnar shape. This also means they'll be expending energy on branch growth, resulting in lower quality fruit.
2. Classic fruit tree varieties grown in columnar form
Any fruit tree can be grown in a columnar form, including apples, pears, plums and cherries. In most cases, the varieties chosen for this purpose are those which are less vigorous and are grafted on dwarfing rootstocks (apples - M9, G 11, M26, M27, B 9; pears - quince ; plums - pixy; plums, apricots and peaches - st. Julien A; cherries and sweet cherries - clare, gisela 5, lake).
However, in order to maiantain the columnar shape of these fruit trees, they need regular pruning. Due to the use of dwarfing rootstocks, the onset of fruiting of these columnar fruit trees is very early (as early as 1 or 2 years after planting). However, the major disadvantages of dwarfing rootstocks is the significantly reduced lifespan and the need for support/staking. The more the rootstock restricts the tree's growth, the lesser its strength/resilience and the shorter its productive life (10-20 years is typical for columnar fruit trees grown on dwarfing rootstocks).
How to grow columnar fruit trees
Columnar fruit tree growing is very simple and, apart from some minor differences, it doesn't differ from the growing of classic fruit trees. They require a sunny location with well/drained soil to thrive. It is advisable to plant several varieties for pollination purposes. Even self-pollinating varieties will produce a better yield and higher-quality fruit when they're cross-polinated. Columnar apple, pear, plum, apricot, peach and cherry trees can be grown outdoors in USDA climate zones 4-8.
The planting of columnar fruit trees doesn't differ in principle from the planting of conventional fruit trees. The spacing between individual columnar fruit trees should be at least 2 feet (60 cm). Particularly in the case of columnar fruit tree varieties grown on dwarfing rootstocks, which have a smaller root system, they'll need support in the form of a sturdy stake.
Pruning of columnar fruit trees
The columnar shape of fruit trees logically requires a different pruning method. Only the central leader branch is left to grow freely and all side shoots are cut back to three buds. In the case of true columnar apple trees, almost no pruning is necessary, except to remove dead and diseased wood.
Summer pruning (June to August) is suitable for pruning columnar apple and pear trees. In the case of stone fruit trees (plums, apricots, cherries), the ideal time for pruning is just after harvest.
Growing columnar fruit trees in pots
One of the advantages of columnar fruit trees is that they can be grown in a variety of containers, but this form of cultivation introduces the need for additional care. First of all, regular watering is important, as the root system of a potted tree is not so drought-resistant. However, the soil must be well-drained and excess water in a tray or saucer should be removed after watering. It is also necessary to regularly provide additional nutrients in the form of compost or natural fertilizer.
Fruit trees in pots need to be transplanted every 2-3 years into a slightly larger pot as they grow, providing a larger space for roots and supplementation of nutrients. The minimum width of the pot for a columnar fruit tree should be 18 inches (45 cm). Columnar potted fruit trees are also prone to frost during the winter, when they may experience rapid changes in temperature (e.g. when the sun warms up the pot and then it starts to freeze quickly), so the pot requires good insulation. In colder climates, columnar fruit trees in pots can be moved indoors for overwintering, to a garage or cellar, where there is no risk of heavy frost, but temperatures must drop regularly below 45°F/7 °C, because most of the fruit tree species need certain minimum count of chill days during winter in order to be fruitful.
Author: Daniel Weber