Dwarf lilac

(Question)

Unlike other dwarf lilacs in the neighbourhood, when mine bloom, the flowers appear below the green, rather than showing on the outside of the bush. They get lots of good sun, and do produce lots of flowers, but they do not show. I have been careful not to use a lot of fertilizer on them. What can I do to correct this? See photo attached. (I started to prune back the green on the lower part of the bush; see top where I have not done this: the green shoots are above the blooms.) Thanks in advance for any advice you can provide! Sara 416-234-0392

 

(Answer)

Thank you for contacting the Toronto Master Gardeners, Sara.

Lilac’s create flowers on the thick buds formed after flowering. These buds are formed through out the summer and lie dormant until the following May or June when they bloom. It would appear that your lilac is very happy where it is and is a very vigorous shrub. This shrub is busy making lots of vegetative growth during the summer after the buds are formed hence the green shoots above the blooms.  It looks like you may need to prune this shrub to keep the dwarf size. The best time to prune lilac shrubs is after they have bloomed but before they have formed the buds for the next year.

There are a number of good sources and websites How to Prune Dwarf Lilac Shrubs & Pruning Lilacs that can be looked at also the Master Gardeners have a great garden guide on Blooming Deciduous Trees and Shrubs that you will find useful.

Happy pruning.