Even a cold north-facing wall can bring delicious fruit with a sour cherry espalier. Sour cherries are robust, easy to grow, and bear lots of fruit every year. Precise pruning is necessary to avoid a balding of the branches and trunk. Sweet cherries are almost never a good choice for an espalier fruit tree. They are very hard to train, are often difficult to pollinate, and are often cleaned out by birds long before the fruit is ripe. Free-standing trees trained as tall spindles are way more promising than sweet cherry espaliers.
(lat.: Prunus cerasus)
Sour cherries do not demand an extraordinary soil. The least optimal soil is heavy, loamy, and damp. They like partially shaded to shaded locations; that is: east, west or even north walls. Sour cherry trees can be found in local tree nurseries or ordered online.
Sour cherries are shaped trees when they are grown on a trellis. Flowering in April / May, Harvest in July / August depending on the variety. Our recommandation-- the new breed "Vogt type morello cherry" ("Vowi"). Important: sour cherry trees are often sold grafted. An ungrafted tree or one that has been grafted on a Prunus mahaleb rootstock should be used for small wall surfaces, in barren sandy soils, and in dry sites. For large trellises, heavy (clayey) soil and in moist sites, a bird cherry rootstock (Prunus avium) should be used. Thin out every 5 - 8 years after the crown of the tree is fully built, right after harvesting. Lightly pruning all shoots every spring reduces the risk of Monilia infection.
Below is a table with all suitable trellis designs. Simple trellises in the "Basic" or "Basic-S" ranges are good choices for a sour cherry espalier; for larger projects- the medium, heavy or massive ranges should be used. The tree is trained to a fan shape on the trellis, without a central stem. The trellis should be built as described in the section on shaped trees, with dominant axes 35 - 40 cm apart.