The appearance of brown, spent hydrangea blooms clinging to the stems in spring is a common sight after winter. While these dried flower heads may seem like an obvious target for cleanup, pruning at the wrong time or location can inadvertently remove the buds for this year’s flowers. Understanding the specific bloom cycle of your plant is the most important factor in determining the correct time and method for removing the old blooms.
Understanding Your Hydrangea’s Bloom Cycle
The timing of pruning depends entirely on whether your hydrangea variety blooms on “old wood” or “new wood.” Old wood bloomers produce flower buds on the previous year’s growth, set in late summer or early fall before winter dormancy. Species like Bigleaf Hydrangea (Hydrangea macrophylla) and Oakleaf Hydrangea (Hydrangea quercifolia) fall into this category. If you prune these varieties heavily in the spring, you cut off the stems containing this year’s bloom set, resulting in few or no summer flowers.
In contrast, new wood bloomers develop their flower buds on the stems that grow during the current spring season. Smooth Hydrangea (Hydrangea arborescens) and Panicle Hydrangea (Hydrangea paniculata) are examples of new wood bloomers. These varieties are more forgiving and can be pruned back hard in late winter or early spring, as the blooms will form on the fresh stems that emerge. For old wood bloomers, spent flowers are usually left on over winter to protect new buds from frost damage, making spring the appropriate time to gently remove them.
How to Identify Your Hydrangea Variety
Identifying the type of hydrangea you have is crucial, as this dictates the correct pruning strategy. One primary marker is the leaf shape, such as the distinctive, deeply lobed foliage of the Oakleaf Hydrangea (H. quercifolia). If your plant has large, oval-shaped leaves with a serrated edge, it is likely a Bigleaf Hydrangea (H. macrophylla), often recognized by its mophead or lacecap flower clusters.
The overall growth habit and flower shape also offer clear clues. Panicle Hydrangeas (H. paniculata) are typically sun-tolerant and often grow into tree-like forms, featuring cone-shaped flower clusters that change color as they age. Smooth Hydrangeas (H. arborescens) are native shrubs with smooth, heart-shaped leaves, famous for their large, white, snowball-shaped blooms.
Proper Deadheading Technique
Deadheading is the practice of removing spent, brown flower heads. The correct technique is to locate the spent bloom and trace the stem down to the first set of plump, healthy buds or leaves beneath it. Make a clean, sharp cut about a quarter-inch above this node, as this is where new growth will emerge.
Use clean, sharp bypass pruners to make a precise cut that minimizes stem damage. For old wood bloomers, be conservative, cutting just below the flower to avoid removing new flower buds set further down the stem. New wood bloomers allow for slightly more aggressive deadheading, as you can cut further down the stem without sacrificing this year’s flowers.
Essential Structural Pruning in Spring
Spring is the ideal time to perform structural pruning to maintain shrub health. This maintenance involves removing the “Three D’s”: wood that is dead, diseased, or damaged. This type of pruning benefits all hydrangea varieties, regardless of their bloom cycle.
Structural pruning involves removing entire stems, unlike the shallow cuts of deadheading. Cut compromised stems back to the ground or to a point where a healthy, outward-facing bud or branch originates. Spring is also the time to thin out weak, crossing, or old, non-productive stems to encourage better air circulation and light penetration. Removing a few of the oldest stems annually promotes vigorous new growth from the base, which is beneficial for mature shrubs.