When to Prune Hydrangeas (Optimal Times)

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Pruning hydrangeas can be a bit tricky since different types of hydrangeas require varying pruning techniques and timing. Generally, when to prune depends on the specific type of hydrangea you have and whether it blooms on new or old wood.

For hydrangeas that bloom on old wood, like bigleaf and mountain hydrangeas, it’s best to prune right after the flowers fade, usually in late summer. You can trim these hydrangeas down to about 12 inches off the ground according to the University of Maryland. On the other hand, hydrangeas like the panicle type, which blooms on new wood, should be pruned back to just above a bud in late winter or spring as suggested by the UMN.

Understanding Hydrangea Types

Oakleaf hydrangea
Oakleaf hydrangea (pictured) is one of the most common hydrangea varieties found in gardens. I, Muritatis, CC BY-SA 3.0, via Wikimedia Commons

There are several types of hydrangeas, each with different pruning requirements based on their blooming habits. This section will help you grasp the differences and know when to prune your hydrangeas.

Bigleaf and Oakleaf Varieties

Bigleaf (Hydrangea macrophylla) and oakleaf (Hydrangea quercifolia) are the most common hydrangea varieties you might find in your garden. These species bloom on old wood, meaning they form their flower buds in the previous year. Here’s what you need to know about pruning them:

  • When to prune: Bigleaf and oakleaf hydrangeas should be pruned just after the flowers fade, usually in summer or early fall. Pruning too late may result in removing the flower buds, causing fewer blooms next year.
  • How to prune: Trim the stems back to about 12 inches off the ground for bigleaf hydrangeas. Oakleaf hydrangeas can be pruned to the same height or left taller for larger-maturing varieties.

Panicle and Smooth Hydrangeas

Panicle (Hydrangea paniculata) and smooth (Hydrangea arborescens) hydrangeas are other popular species that bloom on new wood, which means they produce flowers on the current season’s growth. Here’s a quick overview of pruning these hydrangeas:

  • When to prune: Prune these types in late winter or early spring, before the plant starts its new growth. Some gardeners prefer leaving the dried flower heads on the plants for added winter interest and then pruning in late winter or spring.
  • How to prune: For panicle hydrangeas, make heading cuts by pruning back stems to just above a fat bud. Smooth hydrangeas can be pruned lower to the ground, as they will grow and produce blooms from the base.

Keeping these distinctions in mind will help you prune your hydrangeas at the right time and create stunning, healthy blooms to enjoy all summer long.

Optimal Timing for Pruning

Hydrangea arborescens 'Annabelle' flowers
Hydrangeas that bloom on new wood, such as Hydrangea arborescens (pictured), should be pruned in early spring. KENPEI, CC BY-SA 3.0, via Wikimedia Commons

When it comes to pruning hydrangeas, correct timing is essential. In this section, we will discuss the optimal time for pruning, focusing on early spring, late winter, and summer pruning.

Early Spring Pruning

In early spring, you should prune hydrangeas that bloom on new wood, such as Hydrangea paniculata and Hydrangea arborescens. Prune before new growth has started, as the flower buds grow on the current season’s growth:

  • Cut back stems to just above a fat bud
  • Remove any dead or damaged branches
  • You could shape the plant by removing any branches that cross or crowd

If you’re pruning bigleaf hydrangeas (Hydrangea macrophylla), which bloom on old wood, you can still give them a light trim in early spring. Focus on removing dead or damaged wood, and avoid cutting back any healthy branches that carry flower buds.

Late Winter and Summer Pruning

For hydrangeas that bloom on old wood, like bigleaf, oakleaf, and mountain hydrangeas, it’s best to prune just after the flowers fade, usually in late winter or summer. Here are some steps to follow when pruning these types of hydrangeas:

  • Trim back faded flower heads
  • Don’t remove growth from the present year
  • Prune selectively, avoiding cuts that will remove flower buds

Oakleaf hydrangeas can be pruned to the same height or left taller, depending on your preference and the size of the variety.

Remember, pruning hydrangeas correctly will help your plants maintain optimal health and produce abundant blooms. Keep these tips in mind and enjoy the beautiful flowers your hydrangeas will produce.

Pruning Techniques and Goals

Hydrangea serrata flowers
Mountain hydrangea (pictured) blooms on old wood, so it’s recommended to prune just after the flowers fade. Sabina Bajracharya, CC BY-SA 4.0, via Wikimedia Commons

Shaping and Size Control

When it’s time to prune hydrangeas, your first goal should be shaping and size control. Here are some tips for effective shaping:

  • Focus on removing dead branches and thinning out crowded areas to allow sunlight and airflow.
  • For size control, trim back the stems that have grown too long or that don’t fit the desired shape of your plant.
  • Make clean cuts just above a healthy bud to encourage new growth in the right direction.
  • Keep in mind the natural shape of the specific hydrangea variety when pruning.

Promoting Plant Health and Blooms

Another important aspect of pruning hydrangeas is promoting plant health and encouraging the best possible blooms. Consider these guidelines:

  • For hydrangeas that bloom on old wood, such as bigleaf or mountain hydrangeas, it’s best to prune just after the flowers fade, as this allows the shrub to develop wood that is “old” by the time flower buds emerge.
  • For hydrangeas that bloom on new growth, like smooth or panicle hydrangeas, you can prune during late winter or early spring. This way, flower buds will grow on this season’s growth or new wood.
  • Deadheading, or removing spent flowers, can improve the appearance of the plant and encourage more blooms on some hydrangea varieties.
  • Always use clean, sharp pruning tools to prevent disease transmission and ensure a quick recovery after pruning.

Aftercare and Maintenance

Yellow aphids
Aphids can be an issue for your hydrangeas as they can cause damage to new growth by sucking plant sap. Rego Korosi, CC BY-SA 2.0, via Wikimedia Commons

Fertilizing and Watering

After pruning your hydrangeas, it’s essential to provide proper care to ensure a healthy plant with plenty of blooms. Here are some tips for fertilizing and watering:

  • Apply a slow-release fertilizer in spring and again in mid-summer, especially if you notice slow growth or poor flowering.
  • Hydrangeas prefer moist, well-draining soil. Water regularly, especially during hot, dry periods.
  • Be sure to water at the base of the plant rather than overhead to reduce the risk of diseases.

Monitoring for Pests and Diseases

Keep an eye out for pests and diseases that could affect your hydrangea’s health. Here are some common issues and how to address them:

  • Powdery mildew: This fungal disease causes a white or gray powdery film on leaves. To prevent it, ensure your hydrangea has good air circulation and avoid overhead watering.
  • Leaf spot: Caused by various fungi, leaf spots can result in irregular brown, purple, or gray spots on leaves. Remove affected leaves and avoid wetting the foliage while watering.
  • Aphids: These tiny insects can cause damage to new growth by sucking plant sap. Treat infestations by spraying with insecticidal soap or releasing beneficial insects like ladybugs.
Chris G
About the author

Chris G

Pond consultant and long-time hobbyist who enjoys writing in his spare time and sharing knowledge with other passionate pond owners. Experienced with pond installation, fish stocking, water quality testing, algae control and the troubleshooting of day-to-day pond related problems.

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