Answer: Lilacs do best in full sun all day long and too much shade can definitely reduce their flowering. The most common reason for not flowering however is pruning at the wrong time. Lilacs bloom on wood grown the year before, so any pruning for size or shape should only be done in late spring right after the normal blooming season. Pruning in late summer or fall or early spring will remove flowering wood and flower buds. Finally, lilacs are tolerant of a wide range of pH and soil fertility. Before adding additional lime you should probably run some basic soil tests to check the current pH. Lime is extremely long acting and usually does not need to be added annually. Your local UMASS extension or garden center should be able to help you with the tests and interpreting the results.
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