This section is from the book "The Gardener V1", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
Of these, again, there are several on a north-west wall; but those of the Bigarreau type do not ripen properly, and are much too sour for dessert purposes. Morellos succeed admirably on this site, and again in a north-east aspect; while on the same wall, trees of Late Duke are fast dying. The Morello is also quite at home and very profitable on a north wall. A very hot position appears unsuitable to the choicest Cherries; and oftentimes they are difficult to keep clean on an east wall - aphides being their great enemies. A west aspect then is most suitable to Cherries; and such varieties as Knight's Early Black, May Duke, Black Tartarian, Governor Wood, Elton, Black Eagle, Late Bigarrean, and Late Duke arc worthy of such a position.