Unlike our other cherries, Morello is an acid-cherry (Prunus cerasus) rather than a sweet-cherry, and is grown primarily for culinary purposes. The fruits are smaller than modern dessert cherries, looking more like small seedless grapes. Morello has a strong rich cherry flavour, ideal for cooking. It can be eaten fresh when very ripe (although it is still not sweet).
How to grow Morello cherry trees
Whilst sweet cherries really need a sunny aspect, acid-cherries are far less demanding. Morello can be grown on a north-facing wall if necessary, and is hardy and reliable. It is self-fertile, and the blossom is relatively late, so the risk of frost-damage is slight. The blossom will also pollinate most other late-flowering cherries (sweet or sour).
Acid cherries arguably produce better-looking trees than sweet cherries too. If you need to prune, do so in spring to reduce the risk of bacterial canker, and note that Morello fruits mainly on new shoots which grew the previous summer.