My Annabelle hydrangea, planted in a sun/shade backyard in east end Toronto, has become leggy. Lots of tall green growth but few flowers. I cut it down every fall and now believe that is the source of the problem. How do I fix this for next year?
The fact that your Annabelle hydrangea (Hydrangea arborescens ‘Annabelle’) has few flowers but lots of tall green growth may be due to a couple of things. Even though the Annabelle hydrangeas bloom on new wood, it is best to wait until the late winter or early spring to cut them back; you can then easily see the swelling buds and can prune back the stems to just above the buds. For more information, see: https://www.torontomastergardeners.ca/askagardener/pruning-hydrangeas/.
Secondly, the amount of sun it receives (you have a sun/shade backyard) will affect the number of flowers that the plant produces–more sun will increase the number of flowers. If the hydrangea is being shaded by other shrubs or trees, perhaps a bit of judicious pruning will allow more sun for your hydrangea.
Hydrangeas also prefer somewhat moist conditions–they shouldn’t be allowed to dry out. [Toronto has had minimal consistent rainfall this spring/summer]. You might consider using a mulch of organic material (compost or composted leaves) around the root zone of your hydrangea to help retain moisture as well as to add nutrients to the soil.
Good luck with your Annabelle hydrangea.