Deadheading, the practice of removing spent or faded flowers, is a common technique used to improve a plant’s appearance and redirect energy away from seed production. Whether this action results in a hydrangea reblooming depends entirely on the specific variety of the shrub. For some hydrangeas, deadheading stimulates the formation of new flower buds that will open later in the season. For other types, removing old blooms only serves a cosmetic purpose and will not yield a second flush of flowers. Understanding the growth habit of your hydrangea is key to knowing if deadheading will encourage additional blossoms.
Understanding How Hydrangeas Produce Flowers
Hydrangeas are categorized by the age of the wood on which they form flower buds, which dictates their response to deadheading. “Old wood” bloomers include traditional bigleaf (Hydrangea macrophylla) and oakleaf (Hydrangea quercifolia) hydrangeas. These shrubs develop flower buds on the previous year’s growth, setting them in late summer or early fall. The buds must survive the winter to bloom the following summer.
In contrast, “new wood” bloomers, such as smooth (Hydrangea arborescens) and panicle (Hydrangea paniculata) hydrangeas, form their flower buds on the fresh growth that emerges during the current season. Since the buds develop and open within the same season, they are more tolerant of hard pruning in late winter or early spring. This mechanism makes new wood bloomers generally more reliable for consistent flowering, especially in colder climates where old wood buds might be damaged by frost.
A third category is the “remontant” or reblooming hydrangea, typically a cultivar of the bigleaf type. These varieties produce flowers on both the previous year’s growth and the current season’s new stems. This dual blooming capacity means that if initial flower buds are damaged by winter or removed by early pruning, the plant still generates new buds on the current season’s growth. This characteristic makes them the most responsive to deadheading aimed at encouraging rebloom.
Deadheading Techniques for Repeat Bloomers
For varieties bred to rebloom, the goal of deadheading is to signal that the first reproductive cycle is complete, prompting a second one. This practice is most effective on remontant bigleaf hydrangeas and new wood bloomers like panicle types, which set new buds quickly. Deadheading should occur immediately after the first flush of blooms begins to fade, usually by mid-summer.
To perform the deadheading cut, locate the spent flower head and trace the stem down to the first pair of healthy, full-sized leaves. Make a precise cut just above the node where these two leaves are attached to the stem, using clean, sharp pruners. This specific cut stimulates the dormant lateral buds at that node, encouraging the growth of new stems that will produce a second set of flowers later in the season. Removing the faded flowers promptly redirects the plant’s energy away from seed formation and toward developing new floral structures.
Panicle hydrangeas, which bloom exclusively on new wood, also benefit from deadheading. Removing the spent, often-browning flower heads keeps the plant tidy and encourages the continuous formation of new buds throughout the summer and early fall. Since they are new wood bloomers, the cut can be made further down the stem to shape the plant without sacrificing next year’s bloom.
Deadheading Varieties That Only Bloom Once
For hydrangeas that bloom exclusively on old wood, such as traditional bigleaf and oakleaf varieties, deadheading will not induce rebloom within the same season. The sole purpose of removing spent blossoms is to improve the plant’s aesthetic appearance. Since next year’s flower buds are already forming along the stem below the current bloom, caution must be taken to avoid cutting into the developing tissue.
The technique for these single-blooming varieties involves making the shallowest possible cut, snipping off only the faded flower head. The cut should be made just above the first set of leaves directly underneath the spent bloom. Any cut made further down the stem risks removing the newly formed buds intended for the following year’s flowers.
Because these shrubs set their buds in late summer, any significant cutting back or pruning must be completed right after the shrub finishes blooming, typically before mid-summer. Pruning later in the season, even a simple deadheading cut that is too deep, can inadvertently remove next year’s display. Leaving the spent flowers on the plant over winter is also a common practice, as the dried flower heads can offer a layer of protection to the dormant buds below from harsh weather.