Why Isn’t my Lilac Blooming?

Customer has had lilac for several years and wants to know why it isn’t blooming?

Pruning is the most likely reason. The only time to prune a Bloomerang is immediately after its spring bloom. Pruning at any other time will remove flower buds. And while Bloomerang lilacs are quite deer resistant, I have seen the buds on smaller plants eaten by rabbits who can stand on their hind legs and reach them. I’m assuming it gets at least six hours of bright light each day?

I would advise them to not cut the plant back at all, and start fertilizing it monthly from now until late July. That should help it get extra energy to do some reblooming later this summer.

Where are they located? If they are in a hot climate, that could come into play as well.

To expand on that – all lilacs require a chilling period in order to develop and open their flowers. The length of the chilling period varies by variety and species, and while Bloomerangs and the Scentara series have lower chilling requirements than most lilacs (especially any common lilacs, Syringa vulgaris, the most common type), they still do need some chilling. If a lilac does not get sufficient chilling hours over winter, it will bloom poorly or not at all.