Answer: It is possible that the plant was disturbed, but a more typical reason for lilacs not to bloom is pruning at the wrong time of year. They should only be trimmed in the spring immediately after blooming. Pruning later in the year will remove the following year's flowering wood. Another common reason for poor bloom is lack of sunlight, the plant does bloom best in a full sun location. Lilacs are not too demanding in terms of soil, but an annual application of compost and/or a complete granular fertilizer such as 10-10-10 according to the label instructions might help.
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