Deadheading is the simple removal of spent flowers from a plant, serving both cosmetic and biological purposes. For hydrangeas, this practice immediately improves the shrub’s appearance by eliminating brown, faded blooms and redirects the plant’s energy away from seed production. While the answer to “Should I deadhead my hydrangeas?” is generally yes, the correct method and timing depend entirely on the specific variety you are growing. Getting the timing right is crucial, as improper timing can remove next year’s flowers entirely.
Deadheading Versus Structural Pruning
It is important to understand the difference between deadheading and structural pruning, as the two terms are often confused. Deadheading involves only the removal of the faded flower head, usually by making a small cut just below the bloom itself. This is a superficial, cosmetic procedure that is generally safe to perform throughout the blooming season.
Structural pruning, by contrast, is the removal of live stems or woody branches deeper within the plant’s structure. Gardeners perform this to reduce the shrub’s overall size, improve its shape, or remove older wood. While deadheading is low-risk, improper or ill-timed structural pruning can severely reduce the following year’s flowering display. Deadheading focuses on the flower, whereas pruning focuses on the plant’s woody framework.
The Critical Timing Based on Hydrangea Variety
The correct time to deadhead a hydrangea is determined by its blooming habit: whether it produces flowers on “old wood” or “new wood.” Old wood refers to stems that grew during the previous summer, where flower buds for the next season are set by late summer or early fall. New wood refers to stems that grow in the current season, where the plant develops its flower buds during the spring.
Old Wood Bloomers
Hydrangeas that bloom exclusively on old wood require the most careful timing. This group includes Bigleaf hydrangeas (Hydrangea macrophylla), such as mophead and lacecap types, and Oakleaf hydrangeas (Hydrangea quercifolia). Their flower buds for the following year begin to form on existing stems during late summer. Deadheading these varieties should be completed immediately after the flowers fade in early to mid-summer, and certainly no later than August 1st.
Removing spent blooms after this deadline risks cutting off the developing buds for next season’s flowers. If this narrow window is missed, it is safer to leave the dried blooms on the plant throughout the winter. Remove them only in early spring once the threat of harsh frost has passed. Some reblooming varieties, like those in the ‘Endless Summer’ series, bloom on both old and new wood. While they tolerate deadheading throughout the summer, it should still cease by mid-August to allow the plant to prepare for winter dormancy.
New Wood Bloomers
New wood bloomers are much more forgiving. This group includes Panicle hydrangeas (Hydrangea paniculata), such as ‘Limelight’ and ‘Quick Fire,’ and Smooth hydrangeas (Hydrangea arborescens), like ‘Annabelle.’ Since their flower buds develop on the current season’s growth, there is no risk of removing next year’s blooms by deadheading in late summer or fall. These varieties can be deadheaded at virtually any time of year without compromising the next season’s flowering.
Many gardeners choose to leave the faded flowers on the plant through the winter, as the dried blooms provide visual interest. The final deadheading and any necessary structural pruning for these types is most often performed in late winter or very early spring, before the new growth cycle begins. This timing allows the plant to direct its full energy into the upcoming season’s bud development.
A Simple Guide to Deadheading Hydrangeas
The physical act of deadheading is a straightforward process requiring only a clean, sharp pair of hand pruners or snips. Using sterilized tools is important to prevent the spread of plant diseases. The goal is to remove the faded flower while making a minimal cut into the stem.
Locate the spent bloom and follow the stem downward until you reach the first set of healthy leaves or a visible, opposing bud. This bud is the node where new growth will emerge. Make a clean, precise cut just above this leaf node.
Cutting just above the node ensures that the stem remaining on the plant will not die back, which prevents potential entry points for disease or pests. For reblooming varieties, this action redirects the plant’s energy, encouraging a subsequent flush of new flowers later in the season. Ensure the cut is made at a slight angle to allow water to run off the wound, promoting quicker healing.