I have two French lilac bushes that haven't bloomed since they were planted three years ago. They are small (5 feet) and sparse, but look otherwise healthy. They do receive sun and I see no bugs. I was told sometime ago to try hitting the trunk with a shovel to 'shock' it into blooming, but this did nothing. Any ideas for me?
Lilac Bushes Won’t Bloom
Certified GKH Gardening Expert
It is probably a lack of phosphorus. Add a phosphorus rich fertilizer (normally sold as a "bloom boosting" fertilizer) to the soil. This article will help: https://www.gardeningknowhow.com/ornamental/shrubs/lilac/lilac-bush-not-blooming.htm