Japanese lilac tree

Planted the tree 5 years ago. Flowered every year but not this one. What are possible causes and corrections…

Japanese Lilac not blooming

Dollard des Ormeaux QC (west end on Island of Montreal) Planted 5 years ago. Full sun At the base of the tree I’m growing Thyme is that counter indicated?  Very few blooms this year, not over watered or fertilized –…