Q. I would love to grow sour cherries for canning and baking, but I have a very small city lot that is too small to plant a tree of any size. I have heard of very dwarf sour cherries but cannot remember what they are called. Do you have any information?
A. There are sour cherry hybrids that grow as medium to large shrubs rather than trees. They are the result of breeding work done in the late 1940s by Les Kerr at Canada's Morden Research Centre in Manitoba and later as director of the PFRA Tree Nursery in Saskatoon (now Forestry Farm Park). Mr. Kerr was working to breed dwarf, cold hardy sour cherries that would survive and be productive in the harsh climate of Canada's prairies. His work focused on hybrids developed by crossing sour cherry (Prunus cerasus) and Mongolian cherry (P. fruticosa).
Mr. Kerr donated the germ-plasm developed during his years of research to the University of Saskatchewan, where the research continues today under the leadership of Bob Bors. A number of named cultivars have been selected, including 'Carmine Jewel' and the Romance Series: 'Romeo,' 'Juliet,' 'Cupid,' 'Valentine' and 'Crimson Passion.' You may find that Nanking cherry (Prunus tomentosa) is included with hybrid bush cherries in some catalogs, but according to a 1989 Cornell University publication, "descriptions that emphasize its value for fresh fruit for the home gardener are exaggerated." Nanking cherry is mainly grown as a tough, hardy ornamental shrub.
Bush cherries range in size from 4 to 8 feet tall with a similar spread, depending on the cultivar. They can be grown as a multi-stemmed shrub or trained to a single trunk as best suits your landscape style and available space. Yields average 20-25 pounds per plant, and the fruit is much sweeter than its sour cherry heritage may lead you to believe. Although bush cherries typically do not require cross-pollination for fruit set, planting two or more cultivars increases productivity.
Bush cherries grow best in full sun and well-drained, average garden soil. They are tolerant of clay soils as long as they drain well. In addition to producing delicious fruit, these shrubs boast pretty flowers in spring and dark green, clean foliage that make them attractive ornamental plants. Bush cherries should produce a small crop in their third year, and you may be surprised at how much production jumps the following year.
While growers in Canada report few pest problems, it seems reasonable that some of the same pests that trouble standard cherry growers will cause problems with bush cherries, especially birds. At least shrubs are easier to cover with netting than trees.
Send questions to Sandy Feather by e-mail at firstname.lastname@example.org or by regular mail c/o Penn State Extension, 400 N. Lexington Ave., Pittsburgh 15208.