"Doug Kanter" expounded:

I don't recall, but don't lilacs also like somewhat acidic soil? I don't
know if an imbalance would keep them from blooming, but still, might be
worth checking.

No, they like a neutral to slightly sweet soil. But you're right, a
check of soil pH may be in order.

--
Ann, Gardening in zone 6a
Just south of Boston, MA
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