The University of British Columbia advises setting your hedge cherry plants at intervals equal to the width a mature trimmed hedge. For a 3-foot wide mature hedge, set the plants 3 feet apart.
The amount of sunlight your hedge receives also affects how densely the shrubs grow. Flowering hedge cherries do best in full sun; shade-grown shrubs may be spindly from disease as well as lack of sunlight.
Flowering hedge cherries can be left unpruned to serve as windbreaks or for wildlife. Hedge cherries can grow to about 10 feet in height if left untrimmed. To create a dense hedge with more branches and flowers, keep the shrubs pruned.