I planted an Annabelle hydrangea last summer in Toronto. This year it has no blooms or buds although it is otherwise very healthy. It receives a fair amount of sun but has not dried out given our wet spring. It received compost in early spring and I am adding mulch now. Do you have ideas about why it isn’t blooming? Should I move it to a shadier area of the garden?
Thank-you for consulting the Toronto Master Gardeners.
Annabelle hydrangeas are popular shrubs here in Toronto, partly because they are lovely, and partly because they are reliable performers. It is frustrating that your new one is not preparing to bloom!
Pests and disease can cause blooming problems in hydrangeas, but since you report that your plant looks healthy, it is probably either a cultural problem, or simply because it was only planted last year. Shrubs can take a few years to recover from transplanting. In terms of the environment, you are correct in thinking that the Annabelle hydrangea (a variety of our native woodland Hydrangea arborescens) prefers part shade. Nevertheless, these shrubs can do very well in a sunny situation as long as they have plenty of water. From your description, and given the cool, wet spring here in Toronto, it does not sound as though lack of water has been a problem for your plant. Adding mulch will help to retain moisture as the summer progresses. Your shrub will do better if you ensure it is kept moist in its current location rather that disrupt it by transplanting it.
Over-fertilizing can result in a lack of blooms, but a dose of compost will not have caused that problem.
Incorrect pruning can be a problem with these hydrangeas (you can check on the Toronto Master Gardeners’ web site for some information on pruning), but you do not mention pruning your shrub at all so I am discounting that as the cause of the problem here.
It is possible that your shrub will begin to form buds over the next week or so. The cold wet spring has delayed many plants in blooming. (Mine have only just formed their buds in the last week.) If not, I suggest carrying on as you are and hoping that it has settled into its home and will be ready to bloom next year.
I have included links to a couple of online resources which you might like to consult:
Best of luck!