The question of whether to cut the woody stems, often called “sticks,” from your hydrangea plants is common among gardeners. These shrubs are beloved for their lush, colorful blooms, but their pruning requirements can seem confusing and contradictory. A single, simple answer does not exist because the correct action depends entirely on a fundamental botanical difference within the Hydrangea genus. Ignoring this distinction can result in a year without flowers, while understanding it ensures your plant remains healthy, vigorous, and full of blooms.
Identifying Your Hydrangea Variety
The critical factor determining the proper pruning technique is whether your specific hydrangea variety blooms on “old wood” or “new wood.” Old wood is the growth from the previous season, while new wood refers to the stems that grow in the current season. This distinction dictates when and where the plant forms its flower buds.
Hydrangeas that bloom on new wood include the smooth hydrangea (Hydrangea arborescens), commonly known by the cultivar ‘Annabelle,’ and the panicle hydrangea (Hydrangea paniculata), which includes popular varieties like ‘Limelight’ and ‘Quick Fire.’ These types are typically characterized by their cone-shaped or large, rounded white flowers and their hardier nature. Their flower buds will not develop until the current spring growth begins.
Conversely, hydrangeas that bloom on old wood produce their flower buds on the stems that grew the summer before, and these buds remain dormant on the plant through the winter. This group includes bigleaf hydrangeas (Hydrangea macrophylla), often recognized by their large, globe-shaped “mophead” or flat “lacecap” flowers, and oakleaf hydrangeas (Hydrangea quercifolia). If you prune it heavily in late winter, you will remove your flowers for the coming season.
Cutting Stems on New Wood Bloomers
For hydrangeas that bloom on new wood, cutting the woody stems is generally beneficial and often necessary for maintaining a desirable size and shape. Since the flower buds form on the current season’s growth, pruning can be performed without the risk of sacrificing the upcoming summer’s blooms. The most opportune time to cut these stems is in late winter or very early spring, just before new growth starts.
This timing is preferred because the plant is dormant, making its structure easy to see. Pruning typically involves reducing the plant’s overall size by cutting the stems back by about one-third. You can make each cut just above a pair of healthy, outward-facing buds to direct the new growth away from the center of the shrub.
For smooth hydrangeas, you can prune the entire plant back hard, sometimes to as low as 12 to 18 inches from the ground, to encourage new, strong stems that will support the large flower heads. Panicle hydrangeas also tolerate hard pruning, which helps create a sturdy framework and encourages larger flower clusters. These varieties allow you to control their size and rejuvenate older plants by removing up to one-third of the oldest, thickest stems right down to the ground.
Pruning Old Wood Bloomers
The woody stems of old wood bloomers, such as the bigleaf and oakleaf varieties, should be treated with caution, as they hold the dormant flower buds that will open in the spring and summer. Cutting these “sticks” during the dormant season will remove the flower buds and result in a severe loss of blooms for the entire year.
These hydrangeas should not be cut back aggressively for size reduction; instead, the focus should be on careful shaping and thinning. If any pruning is necessary, it must be done immediately after the flowers have faded, typically in mid-to-late summer, and no later than July. Pruning after this window does not allow the plant enough time to produce new growth and set the buds for the following year’s display.
When pruning, only remove spent flower heads by cutting back to the first set of large, healthy leaves. To manage the size or shape of the shrub, selectively remove no more than one-third of the oldest, thickest canes right down to the base of the plant. This method, called renewal pruning, encourages the development of new, productive stems without removing the majority of the current year’s flower production.
Removing Dead, Damaged, or Diseased Stems
Regardless of whether a hydrangea blooms on old wood or new wood, there is one universal exception to all pruning rules: the immediate removal of any dead, damaged, or diseased stems. This maintenance task should be performed at any time of year. These compromised stems, often called the “three D’s,” are a liability to the plant’s overall health and do not contribute to future flowering.
Dead stems are usually brittle and gray or brown, lacking any green tissue when scraped lightly with a fingernail. Damaged stems may be cracked, broken, or rubbed raw, often from wind, snow, or neighboring branches. Diseased stems can show signs like discoloration, cankers, or a soft, mushy texture.
Removing this material prevents the potential spread of pathogens and pests to the healthy parts of the shrub. Using sharp, sanitized pruning shears, cut the affected stem back to a healthy section of wood or all the way to the ground. This proactive removal is a form of sanitation that helps ensure the plant directs its energy toward vigorous new growth and abundant blooms.