When to prune hydrangeas

Gardening Tips

By Lisa Walmsley

  • When to prune hydrangeas image

I have found over the years that folk either love or hate hydrangeas. In my mind, every plant has a place and this one is particularly good in those shady spots in your garden, where a lot of other plants will not grow. However they are not a set and forget plant and a little care will guarantee glorious flowers in the summer.

Pruning hydrangeas can be confusing. When you google, ‘How to prune hydrangeas’, the usual chaos of mixed and conflicting information occurs. The main concern is that pruning incorrectly will lead to your hydrangeas not flowering and really if they don’t flower, what is the point of having them.

The reason they can be a little tricky to prune is because some hydrangeas bloom on new wood, that is the current seasons growth, while other flower on old wood, last seasons growth.

During pruning

Making this all more complicated is the fact that in our cold climate, old wood hydrangeas can fail, even when following the old wood pruning rules.

Most of the hydrangeas in this little part of our world bloom on new wood. This means the flowers bloom on flower buds that formed in that season. These flower buds were not on the plant during the winter months. The buds were developed during new growth in spring.

These hydrangeas should be pruned in late winter or early spring, before the plant starts to put on new growth.

To make things a little confusing there are a few choices when is comes to pruning new wood hydrangeas. Sometimes you will cut the plant back to within a couple inches of the ground. At other times you will require to cut the plant back to 1/3 of its size.


To simplify this, you need to know which type of hydrangea you have. New wood hydrangeas are either Annabelles or Panicles.

Annabelles can be pruned close to the ground, leaving a few inches of last years wood to create support structure for new growth.

Panicle hydrangeas don’t need to be cut back so hard and you will leave 1/3 of the plant above ground.

Some of the old wood hydrangeas include, Oakleaf and climbing hydrangea and although some of these survive in our climate, many die or are hard to grow, especially if you live in an area with lots of frosts.

I like a different style of pruning, selective pruning. This involves selectively cutting our branches that are dead, diseased or old and spent flowers. Also cutting out cross branches that are rubbing each other.

And if this all seems too complicated, you don’t have to prune your hydrangeas. The benefits of pruning are shaping the plant, and maintaining size and vigour. If you think your plants are a good size and shape and healthy they will be fine left to their own devices.

If you have followed all the general rules of maintaining hydrangeas and they are still not flowering there are a few main reasons:

  1. Old wood hydrangeas in a cold climate will die back in harsh winters
  2. Pruning old wood hydrangeas after flower buds have developed
  3. Plants are still not mature enough
  4. Not enough sun – four hours is good
  5. Possums love hydrangea flower buds

And don’t forget to add a tablespoon of baking soda to a full watering can of water every two weeks as the plant starts to grow in spring.


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