Cordon training is suitable for all pears and apples that bear fruit on short sideshoots (spur-bearing). The term 'cordon' simply refers to a single stem with short sideshoots (the fruiting spurs). This is usually trained angled to 45 degrees, but can be trained vertically. Angled cordons are more productive and less prone to getting out of hand. They are trained against a wall, fence or on wires between free-standing posts.
Unfortunately, vigorous cultivars are difficult to keep within bounds so make poor cordons. Likewise, cultivars that bear fruit at the tips of their branches (tip-bearing) are difficult to prune in this way as the tips need to be pruned off and so little fruit is borne. Those apples and pears that bear fruit on both tips and side shoots, known as partial tip-bearers, can be grown as cordons if some short branches are left unpruned each year.
When to prune and train a cordon
Choose an open, sheltered position, avoiding frost-prone sites, if possible. Soils should be well-drained, moisture-retentive and not prone to waterlogging.
The best time for planting cordons is in winter. Use one-, two- or three-year-old cordons. When buying cordons, you will have a choice of rootstocks. Use M27 rootstock (extremely dwarfing) or M9 rootstock (very dwarfing) for apples where the soil is fertile; otherwise, use M26 rootstock (dwarfing). Pears are best grafted on Quince C or, for very poor soils, Quince A.
Plant trees at an angle of 45 degrees. Cordons will need support so you will need to plant against a wall, fence or on three horizontal wires, 60cm (2ft) apart, stretched between posts, 2m (6ft) apart.
If planting more than one cordon, space at 60-90cm (2-3ft) apart. Cordons can be allowed to reach a height of about 1.5-2m (5-6½ft) so take that into consideration when planting.
After planting, cut back all laterals longer than 10cm (4in) to three buds, leaving the leader and any short laterals.
Vertical and double cordons (‘U’-shaped) can also be grown in containers (at least 45cm (18in) wide) in John Innes No. 3 compost (a soil-based potting media that is easy to manage and heavy enough for the pot to be stable).
How to prune and train a cordon
Summer pruning an oblique cordon (at 45 degrees)
Summer pruning is carried out in August, or in areas where growth is strong, such as wet parts of the country, delay summer pruning until September.
- Look for sideshoots over 22cm (9in) long, which grew earlier in summer directly from the main stem, and cut them back to three leaves. Those stems that grew from existing sideshoots or spurs can be pruned harder - to just one leaf beyond the cluster of leaves the base of that stem
- Leave shoots less than 15cm (6in) long until mid September and then shorten to one leaf beyond the cluster of leaves the base
- Prune growth that forms after summer pruning in September (or October if pruning later)
Winter pruning oblique cordons
- Neither the leader nor side shoots are normally pruned in the winter, except where the tree has grown a lot since summer pruning or you need to renovate a neglected tree
- When the cordons reach the top wire they may be lowered from 45 degrees to not less than 35 degrees (as there is less risk of the stem breaking). This will increase the length of stem, and so the amount of fruit produced. Once the cordon has reached the final length, prune back the leader to 1cm (½in) each May
- Over-long or complicated spur clusters should be reduced to two or three fruit buds
How to prune minarettes and ballerinas
Vertical cordons, sometimes called ‘minarettes’, lack the inhibiting effect that the angling and bending of the stems provides on oblique and double cordons. As a result, they are harder to train and prune because they want to turn into small trees. However, they are still useful in small gardens so here are some growing tips:
- Plant ready-formed minarettes or maidens (a young tree without the development of sideshoots)
- Tie to a vertical, 2.4m (8ft) tall bamboo cane
- Allow at least 60cm (2ft) between trees
- Encourage the lower buds to break on maidens by shortening the leader by one-third of its height each winter until it reaches the top of the stake
- Otherwise, prune as for the oblique cordon (above)
Ballerina apples have been bred for a columnar habit that needs no pruning other than occasional shortening of sideshoots and leading, or top shoot. Thin out spurs in winter when congested. Ballerina trees are convenient in small gardens or where pruning skill is uncertain. Unfortunately, Ballerinas have less flavour than conventional apples and are also prone to disease.