This is my fault as I should have the read my response before I posted it. But the libray was closing and I was running out of time. Whenever, I plant anything. I put a mixture of topsoil, compost and the original soil that I dug out. That way I don't get the bathrub effect which would kill most of my garden, the other trees I planted which bloom just fine and my all roses. Other thing, is I also use earthright once or twice a year. I haven't yet this year but I have to this month or I have to wait until fall. Like I said I did talk to Johnson county garden extension office that told me that it might be growing issue. As the tree has really taken off in the last two year. The other times it didn't bloom were to late freeze but this year that shouldn't been an issue. In early May the lowest we got was 38 which did affect some of the leaves but not enough to keep it from blooming. There are some blooming in a near by city. Ants are not an issue because they prefer my Pin oak.

Syringa reticulata and Syringa pekinensis have both been available in the United States since the late 1800s. I have personally managed individuals from the turn of the century (early 1900s). These plants can be grown as multi-stemmed or single-stemmed small trees. That is a choice made by nurserymen growing the plant originally, and afterward by the party responsible for the landscape in which the tree is planted. There are a number of narrow selections of Syringa reticulata - 'Ivory Silk' is a popular and very common one. 'Ivory Tower' is another. These will have smoother gray bark. Syringa pekinensis is more variable in bark and form. A selection named 'China Snow' has fabulously exfoliating/peeling bark, competing with some of the ornamental cherries. It doesn't seem to have as heavy a flower display as many of the Japanese Tree Lilac clones. Bernheim has a collection of old specimens dating to the 1960s here in KY. These are durable plants, and ought to be used more widely.

Flowers are born on last year's wood, so if one must be pruned, do it immediately after it has ceased blooming. I have Summer Snow and mine has only been planted two years now, and has yet to bloom, so I'm not a good resource to give you any information you couldn't get by a web search. I do know that they do like sun in your zone and that they prefer sweet soil and should likely have no supplemental nitrogen unless you are sure your soil is deficient.

patience is usually what's needed.