Pruning Your Hydrangeas: A Step-by-Step Guide for a Blooming Garden

Mastering Hydrangea Pruning: A Gardener’s Guide

Hydrangeas, with their lush blooms and vibrant colors, are a beloved addition to gardens across the country. However, these beautiful shrubs can quickly become overgrown without proper care, including regular pruning. This guide provides essential tips and techniques for pruning hydrangeas, ensuring your plants thrive and produce an abundance of stunning flowers.

Understanding Hydrangea Types

Before you begin pruning, it’s crucial to identify the type of hydrangea you have, as different varieties require different pruning approaches. The timing and method of pruning hinge on when and where the plant produces its flowers. Here’s a breakdown of common hydrangea types and their pruning needs:

• Bigleaf Hydrangeas (Hydrangea macrophylla): These are among the most popular, known for their large, mophead (hortensia) or lacecap blooms. They include varieties like ‘Endless Summer’ and other reblooming types. Bigleaf hydrangeas typically bloom on old wood, meaning the flower buds are formed on the previous year’s growth.

• Smooth Hydrangeas (Hydrangea arborescens): This group includes the classic ‘Annabelle’ hydrangea, known for its large, snowball-like flowers. Smooth hydrangeas bloom on new wood, meaning they produce flowers on the current season’s growth.

• Panicle Hydrangeas (Hydrangea paniculata): These hydrangeas, such as ‘Limelight’ and ‘Pinky Winky,’ are known for their cone-shaped flower clusters. Panicle hydrangeas also bloom on new wood.

• Oakleaf Hydrangeas (Hydrangea quercifolia): Named for their oak-like leaves, these hydrangeas are known for their unique foliage and large, cone-shaped blooms. Oakleaf hydrangeas bloom on old wood.

• Climbing Hydrangeas (Hydrangea petiolaris): This is a climbing vine that produces white, lacecap flowers. It blooms on old wood.

Pruning Tools: What You’ll Need

Having the right tools will make pruning easier and more effective:

• Hand pruners: For smaller stems and branches.
• Loppers: For cutting thicker branches.
• Pruning saw: For removing larger, older branches.
• Gloves: To protect your hands.
• Safety glasses: To protect your eyes.
• Rubbing alcohol: To disinfect your tools between cuts, preventing the spread of disease.

General Pruning Principles

Regardless of the hydrangea type, there are some general principles to keep in mind:

• Remove dead or diseased wood: This should be done whenever you notice it, regardless of the season. Cut the affected stems back to healthy wood.
• Thin out crowded stems: This improves air circulation and light penetration, which can help prevent fungal diseases and encourage better flowering.
• Remove crossing branches: These can rub against each other, causing damage.
• Cut back to a healthy bud or branch: Make your cuts just above a bud or where a side branch joins the main stem.
• Avoid excessive pruning: Over-pruning can reduce the number of flowers, especially on hydrangeas that bloom on old wood.

Pruning Specific Hydrangea Types

Bigleaf Hydrangeas (Hydrangea macrophylla)

• Pruning time: Late summer, after the flowers have faded, or very early spring, before new growth begins. Avoid pruning in late fall or winter, as this can remove the flower buds.
• Pruning method:
  • Remove dead or diseased wood.
  • Thin out crowded stems.
  • Cut back any stems that have been damaged by winter weather.
  • You can also cut back the entire plant by about one-third to encourage new growth and more compact form.
  • Deadhead spent blooms by cutting the flower stem back to the first set of healthy leaves.

Smooth Hydrangeas (Hydrangea arborescens)

• Pruning time: Late winter or early spring.
• Pruning method:
  • Cut the entire plant back to about 12 inches from the ground.
  • This encourages strong new growth and large flowers.
  • Remove any dead or weak stems.

Panicle Hydrangeas (Hydrangea paniculata)

• Pruning time: Late winter or early spring.
• Pruning method:
  • Cut back the previous year’s growth by about one-third to one-half.
  • This encourages larger flower heads and a more compact form.
  • Remove any dead or weak stems.

Oakleaf Hydrangeas (Hydrangea quercifolia)

• Pruning time: Late summer, after flowering.
• Pruning method:
  • Remove dead or diseased wood.
  • Thin out crowded stems.
  • Cut back any stems that have been damaged by winter weather.
  • Avoid heavy pruning, as this can reduce flowering.
  • Deadhead spent blooms.

Climbing Hydrangeas (Hydrangea petiolaris)

• Pruning time: Late summer, after flowering, or early spring.
• Pruning method:
  • Remove dead or diseased wood.
  • Thin out crowded stems.
  • Cut back any stems that are growing away from the support.
  • Prune to shape the plant and keep it within its allotted space.

Addressing Overgrown Hydrangeas

If your hydrangeas have become overgrown, you can take steps to rejuvenate them:

• For bigleaf hydrangeas: You can prune up to one-third of the plant’s height in late summer after flowering to encourage new growth. Be careful not to over prune, especially if the plant is an older variety that blooms on old wood.
• For smooth and panicle hydrangeas: These types are more forgiving and can be cut back more severely. In late winter or early spring, cut the entire plant back to about 12 inches from the ground to rejuvenate it.

Common Pruning Mistakes to Avoid

• Pruning at the wrong time: This is the most common mistake. Always know the blooming habits of your hydrangea type and prune accordingly.
• Over-pruning: Removing too much of the plant can reduce or eliminate flowering.
• Using dull tools: Dull tools can tear the stems, making them susceptible to disease. Always use sharp, clean tools.
• Not disinfecting tools: This can spread diseases from one plant to another.

Hydrangeas in Chicago: Climate Considerations

Chicago’s climate presents some challenges for hydrangea growers, particularly with bigleaf hydrangeas, which can be susceptible to winter damage. Consider these tips:

• Choose cold-hardy varieties: Select hydrangea varieties known to thrive in colder climates. ‘Endless Summer’ and other reblooming bigleaf varieties are often good choices.
• Provide winter protection: In late fall, protect your hydrangeas from harsh winter winds and cold temperatures by:
  • Wrapping the plants with burlap.
  • Mounding mulch around the base of the plant.
  • Using a frame to protect the plant.
• Plant in a sheltered location: Plant hydrangeas in a location that provides some protection from winter winds, such as near a building or fence.

Conclusion

Pruning hydrangeas may seem daunting, but with the right knowledge and techniques, it’s a manageable task that yields beautiful results. By understanding the different types of hydrangeas, using the correct tools, and following the appropriate pruning methods, you can ensure your plants flourish, providing stunning blooms year after year. Remember to consider your local climate and the specific needs of your hydrangea varieties for optimal success. With proper care and pruning, your hydrangeas will undoubtedly become a highlight of your garden.