Lilacs not flowering
I've read your article on non blooming lilacs and have tried your suggestions. I've had these small 4 ft tall lilacs for 20 yrs and never a bloom! I've tried transplanting suckers and even whole bushes to a sunnier location but the most they get is 4-5 hours of sun, and do not flower. They seem to bloom on every side road, untended and wild. Why can't mine bloom?
Full sun is 6 plus hours of sunlight, a Lilac needs this amount of sunlight and also the correct amount of chill in the winter to flower.
I would suggest a soil test to determine what may be going on in the soil conditions.
Your County Extension Office can help you with a soil test.
Here is a link to help you locate your nearest office.