I've got an oakleaf hydrangea and a smoke bush which both grow huge and healthy looking each summer, but neither has flowered for over 10 years (they were planted 11 years ago). I prune them back in late fall. What can I do to get them to bloom?
Making Bushes Bloom
Certified GKH Gardening Expert
I would suspect that they have too little phosphorus, especially if they are planted near a lawn area that gets regularly fertilized. This article will explain more: https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/phosphorus-plant-growth.htm