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When and How To Prune Hydrangeas By Type

With 4 basic types of Hydrangeas you need to know how to prune Hydrangeas by variety as they are pruned in different ways and at different times of the year.

When and How To Prune Hydrangeas
When and How To Prune Hydrangeas

Common Hydrangea Types

  • Macrophylla – Commonly called Big Leaf, Mop Head, and Lacecap (Hydrangea macrophylla normalis) and Mountain (Hydrangea macrophylla Serrata)
  • Arborescens – Commonly called Smooth Bark or Wild Hydrangea.
  • Paniculata – Commonly called Peegee as well as Panicle Hydrangea
  • Quercifolia – Commonly called Oak Leaf

All are pruned slightly directly and the time of the year that you prune them is important if you want flowers the next season.

So here is a guide to how we prune 4 different types of Hydrangea.

How To Prune Hydrangeas – Techniques for different varieties

Some Hydrangeas flower on old growth, others on new growth. This is where pruning techniques will differ.

H. paniculata or Pee Gee hydrangeas are pruned in winter.

Paniculata hydrangeas often called PeeGee ( from the common form H.paniculata grandiflora or PG). These are a woody late flowering shrub that flower on new wood, these are the the ones with the ‘cone shaped’ flowers. You can deadhead them at any time, or prune them back from winter to spring. They are one of the easiest to prune and can be trained to form a single trunk, a bit like a standard. Prune about any time except when they have started to form the new flower buds.

  1. Remove any dead or damaged wood back to the stem.
  2. Prune all of last years growth back to 2 buds. You may need to go to 1 or 3 buds depending on the shade of the plant.
  3. Prune all of last years growth back to 2 buds. You may need to go to 1 or 3 buds depending on the shade of the plant.
  4. With any congested points in the plant, prune back to a node on the stem below the congestion.

Pruning Smooth Hydrangeas (Hydrangea arborescens) Types

Annabelles, which are a common variety of Hydrangea arborescens flower on new wood and can be cut right back. These are a white flowering type that form large flowers to 25cm (10″) across. As they flower on new growth they can be pruned back hard every year. Best time to to prune is in winter.

  1. These are easy Hydrangeas to grow and are pruned from autumn to winter but best in early spring just as new growth appears. Plant at 4ft apart
  2. They flower on the tip of the stems
  3. Prune all of the old dead shoots back to ground level.
  4. You will see new shoots appearing at the base of elf the plant.
  5. Prune all of last years stem back to 2 sets of buds or 6 inches or so from the base.
  6. Remove any weak or spindly stems completely.
  7. Now its a good time to fertilise these hydrangeas, use a balance slow release type fertiliser, a few handfuls around the plant and water in.

How To Prune Macrophylla or big leaf hydrangea.

These are plants that flower on last years wood (old growth), they form the flower buds the summer before, so if you hard prune they will have very few flowers.

Mop Heads types are Hydrangea macrophylla also known as Endless summer or Big leaf. Generally they flower on both last years and this years wood, and they are bred this way.

Lacecape types are Hydrangea macrophylla normalis and we think they are one of the most attractive types. They are pruned the same way as Mop Heads

  1. These are pruned in summer as the flowers begin to fade.
  2. In winter when the leaves are off the plant prune all of the old dead wood from the plant.
  3. This relieves congestion in the centre of the plant and improves air flow.
  4. In summer, remove any dead wood from the tips of the stems.
  5. Remove any crossing or errant stems.
  6. In summer you will see new green shoots with no flowers and older grey to brown shoots with flowers. These shoots are pruned back by around 1/3 to a strong set of green shoots.
  7. Now trim those all of green shoots back to 2 or 3 sets of buds
  8. Now prune back any thin spindly shoots.
  9. You can also decide to lower the height of the plant by pruning back a little more.

With some remontant types (plants that flower more than once, so ‘flowering again) Macrophylla types you can get a second flush of flowers in late summer to autumn.

OakLeaf Hydrangeas

Characterized by the large oak leaf shaped foliage, flowers come as doubles and singles. They are woody and require little pruning at all, these are a hydrangea that prefer warm to hot summers, prune lightly after f lowering

  1. Pruning is usually restricted to dead heading old flowers.
  2. If they get too large the prune them after flowering if you want flowers for next year.
  3. Damaged, dead, diseased or errant growing wood.
  4. You can prune them back to size if needed and this can be done in spring, just remember that you will not get flowers that year.

How To Prune Hydrangeas that flower on old growth

  • Identify dead wood or canes and use some loppers to cut these right back to good wood, or the ground.
  • If you have an old plant that need a little rejuvenation, remove up to 1/3 of the old canes back to the ground.
  • You should have a bush that is well formed and reasonably open, this promotes good air flow, if not remove other old canes to shape.
  • Cut back all growth to the second set of buds from the top. Then remove any weak growth.
  • Have a break and evaluate the shape of the plant, you could stop here, however if the plant is getting to tall you may need to look for buds lower down to prune to.

How To Prune Hydrangeas that flower on new growth

Some gardeners simply cut them back to the ground each year, however we suggest

  • Removing old dead wood. 
  • Pruning away some of the smaller growth at ground level and leaving the strong older stems that are best formed.
  • Open up the centre of the plant a little by removing ‘crossover’ growth.

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