Sour Cherry

Prunus cerasus

Sour cherries are smaller, softer, and much more acidic than familiar supermarket sweet cherries. They are a separate species, not simply sweet cherries picked before ripening.

Sour cherry trees are naturally smaller and generally more winter-hardy than sweet cherry trees. Maine growers still contend with tender flower buds and spring freezes, but cultivars such as North Star, Meteor, Mesabi, and Evans can reach into Zone 4 conditions.¹

Many sour cherries are self-fertile, so one tree can set fruit on its own. Many sweet-cherry cultivars are self-incompatible and need compatible pollen from another cultivar—an important biological difference hidden behind two similar fruits.²

Montmorency became the dominant North American sour-cherry cultivar as commercial orchard production specialized in the late nineteenth and early twentieth centuries.³

Sweet and sour cherries differ most fundamentally in how much sugar they can accumulate; sour cherries are not simply harvested earlier.⁴ Much of cherry aroma comes from almond-like benzaldehyde, floral linalool, and clove-like eugenol. Heating strengthens the almond and floral notes, especially when pits remain present.⁴

The species itself is a natural hybrid: USDA describes P. cerasus as a tetraploid descended from sweet cherry (P. avium) and European dwarf cherry (P. fruticosa). Its tartness is not a fixed number, either. Across the USDA collection, measured malic acid and soluble solids vary widely among accessions, which helps explain why two tart cherries can behave differently in a pie or preserve even when both carry the same broad name.⁵