Deadheading is a common practice in gardening that prompts many questions when applied to hydrangeas. Whether you need to deadhead depends on the variety of your plant and the gardener’s aesthetic goals. Hydrangeas are classified by whether they bloom on “old wood” or “new wood,” meaning the timing and necessity of this task are not universal. Understanding this distinction is the first step toward promoting a healthy plant and ensuring a colorful display next year.
The Purpose of Deadheading
Gardeners perform deadheading for aesthetic reasons and to redirect the plant’s energy resources. Removing faded, browning, or wilted flower heads improves the overall appearance of the shrub, keeping it tidy throughout the growing season. This practice also prevents spent blooms from collecting water and causing the branches to flop or break, which helps maintain the plant’s structural integrity.
Deadheading maximizes the plant’s vigor by preventing seed production. By removing the flower, the plant channels energy into root and stem development or, for reblooming varieties, into producing new flower heads. This energy redirection results in a stronger, healthier shrub and can extend the blooming period for certain cultivars.
Instructions for Old Wood Bloomers
For hydrangeas that bloom on growth from the previous year, deadheading requires caution and precise timing. This category includes the popular Bigleaf (Mophead) and the Oakleaf hydrangeas. Deadheading is often not strictly necessary for the health of these varieties, but if you choose to tidy them, it must be done immediately after the flowers fade in early to mid-summer.
The danger comes from cutting too late in the season. These varieties set their flower buds for the following year during late summer and early fall. Cutting the stems after approximately mid-August risks removing the newly formed buds, which will compromise the next summer’s flower production. Many gardeners opt to leave the spent blooms on the plant through winter, as the dried flower heads can offer a degree of protection for the dormant buds from harsh weather.
Instructions for New Wood Bloomers
Deadheading is a flexible practice for hydrangeas that bloom on new wood, meaning the current season’s growth. The most common examples of this type are the Panicle and the Smooth hydrangeas. Because the flower buds form in the spring of the same year they bloom, a late cut will not affect the following season’s flowers.
These varieties, especially Panicle hydrangeas, often produce large, heavy flower heads that can weigh down the stems. Deadheading helps alleviate this weight, preventing the branches from bending or splaying outward and maintaining a more upright, structurally sound shrub. Gardeners can deadhead spent blooms throughout the summer for a cleaner appearance, or remove the faded flowers any time from late summer through late winter or early spring before the new growth cycle begins.
Making the Cut: Practical Technique
Deadheading is straightforward, provided you use the proper tools and aim for the correct location on the stem. Always use a pair of clean, sharp hand pruners or snips to make a precise cut, which minimizes damage to the plant and reduces the risk of introducing disease.
To remove a spent bloom, trace the stem down from the faded flower head until you encounter the first set of healthy leaves. Make a clean, angled cut just above the point where those leaves attach to the stem. Cutting here ensures that the remaining stem segment is minimal and encourages new growth to emerge from the healthy bud just above the cut.