Would you kindly advise me when and how to prune the hydrangea in this photo? Also tell me what kind it is.
Thank you for contacting the Toronto Master Gardeners with your inquiry.
The shrub in your photo is a Hydrangea paniculata ‘Pinky Winky’. Flowers on panicle hydrangeas are panicle-shaped (cone-shaped), in contrast to the ball-shaped mopheads or flattened lacecaps. Paniculata type hydrangeas are hardy hydrangeas that can withstand harsh winters. The flowers develop on new wood each year which means that they can be pruned any time of the year except summer. The blossoms that are on the plant now will dry out and provide winter interest. Most people prefer to prune them in late winter or early spring because it is easier to see the branch structure. Wait until after the worst winter frosts, but before they start to grow vigorously. You don’t have to prune them each year, however removing about 1/3 of the oldest branches each year creates a fuller and healthier shrub.
I highly recommend the following video available on You Tube, which shows clearly and in detail how to prune a 4-year-old hydrangea How to Prune Tree Hydrangea 1 of 3 | Hydrangea paniculata – YouTube