After looking on you tube it seemed that the tip of the oak leaf hydrangea branches should be removed because it suppressed the growth of flowers all over the plant. I removed all except 2 and those were the only two two produce flowers. What is the way to go?
Thank you for contacting the Toronto Master Gardeners about your oakleaf hydrangea (Hydrangea quercifolia). Unlike some other types of hydrangea, oakleaf hydrangea does not require pruning except to remove dead, damaged or diseased stems (these are usually removed at ground level), or to shape or manage the size of the shrub. So pruning this shrub is done very infrequently, as needed, not as a regular annual practice.
Oakleaf hydrangea does require deadheading every year. Deadheading is the removal of dead flower heads, which can be done either as soon as the flowers have faded or in the early spring. Dead flower heads are removed just below the flower.
One of the main reasons for oakleaf hydrangea failure to bloom or producing very few flowers is that pruning (when it was done) was done at the wrong time. These shrubs bloom on old wood, that is wood that was on the shrub in the previous year. If pruning is going to be done, it should be as soon as the flowers have faded, because very soon after that the shrub will start to develop the buds for next year’s flowers and these buds will be set by late summer. So if you wait to prune, you will probably be removing buds that would have become next year’s flowers.
Other reasons for poor or no blooming on oakleaf hydrangea are: not enough sunlight (this shrub needs a good half day of sun, preferably in the morning), winter injury (these shrubs are hardy to zone 6, so they are just on the borderline for winter survival in the Toronto area), late freeze in the spring (which will kill the buds) and too much fertilizer (specifically too much nitrogen which will result in lots of green leaves at the expense of blooms).
Oakleaf hydrangea is fairly easy to care for: half-day full sun in moist, well-drained soil; drought tolerant when established; no or minimal pruning needed; few pests and diseases. This article has lots of good information about oakleaf hydrangea.
If you do need to prune your oakleaf hydrangea to remove dead or damaged or diseased wood or to manage it’s shape and size, here is a good video that covers the basics.
I hope you have lots of flowers on your oakleaf hydrangea next year and for years to come!