How to prune hydrangeas

Ensure a good shape and maximum flowers by pruning in early spring

Hydrangeas are one of the most popular garden shrubs, and rightly so. There are two main types that we tend to grow, though there are many more out there – the most popular being the mophead hydrangea or Hydrangea macrophylla. You will notice at this time of year that the buds on your hydrangea are starting to swell and may have even broken into young leaves; that is a clear indication of viability. It means that you can start to identify those parts of the shrub – normally the tips – that have been damaged by the winter.
The first thing to do with a mophead hydrangea is to remove any deadwood or any stems that may have been damaged by rubbing, or by an animal. 
Secondly, look at removing around 25 per cent of the shrub at the base, focusing on the oldest wood. The reasoning behind this is that we should try to rejuvenate the plant every year, and over time we are replacing the oldest stems with younger, vigorous and more floriferous wood.
Having removed the dead wood and a proportion of the old wood, we now need to look at the symmetry of the shrub. Create a slightly open centre, pruning back to a pair of strong, healthy buds, with the ambition of creating a symmetrical and aesthetically pleasing shape. Be warned that the harder you prune, the more likely it is that you will end up with lots of leafy growth and fewer flowers, so be tentative and only reduce those stems by 20 per cent or so.
Hydrangea paniculata is a stunning shrub and has lovely, large, white and blush-pink flowers in summer. This species of hydrangea differs from the mophead in that we need to reduce last year’s growth back to a pair of buds.
You can manipulate the timing and size of the flowers on Hydrangea paniculata by the severity with which you prune last year’s growth back. Taking it back to two pairs of buds from its origin will create large flowers that appear a little later in the season, whereas if you simply reduce that stem back to six or seven pairs of buds, you will achieve more flowers, but they will be smaller and a little earlier.
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