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When To Prune Oakleaf Hydrangeas? (And How To Do It Right)

Oakleaf Hydrangeas are a prized addition to gardens, yet many gardeners are uncertain about the proper pruning techniques for these plants, often due to limited information available online. Pruning hydrangeas typically involves deadheading, which means removing the spent flower clusters.

For oakleaf hydrangeas, the ideal time to prune is in the summer, immediately after the flowers have faded. These plants thrive in full sunlight but can also tolerate partial shade. However, excessive shade may hinder their blooming.

When to deadhead hydrangeas?

To effectively deadhead hydrangeas, it’s important to start when the flowers begin to fade. The timing of this can vary depending on the variety of hydrangea. By removing the faded flower clusters, you encourage the growth of new blooms. Use sharp, sterile scissors for pruning, preferably those that are long and thin for precise cuts.

However, from fall onwards, it’s advisable not to deadhead hydrangeas. Instead, leave the old flower heads on the plant until spring. This approach helps the plant conserve energy, leading to larger and more vibrant flowers the following year.

When pruning, make sure to cut the flower clusters at the point where they join the stem. Avoid cutting below this junction as it may harm the buds responsible for future flower growth, resulting in fewer blooms.

When to prune for shape?

Pruning hydrangeas for shape or size reduction is a common gardening task. Since hydrangeas bloom on old wood, excessive pruning can significantly reduce the number of flowers or even prevent them from appearing. The optimal time for shaping or shortening hydrangeas is in the spring, typically around March or April, though this can vary based on your local Hardiness zone. Spring pruning allows the plant to recover from pruning wounds during the growing season and prepare for the next year’s bloom.

When pruning, it’s crucial to use the right technique. If your goal is to slightly reduce the plant’s size or shape it into a large sphere, cut the stems no more than a quarter of their length, or around 1-2 leaf nodes from the top.

Avoid damaging the flower buds located in the leaf nodes above the mid-length of the stem, as this ensures the hydrangea will still bloom in the current year, although the number of inflorescences might decrease depending on how much you trim.

Use quality, well-sharpened, and antiseptically cleaned pruning shears for this task. Make your cuts in the middle of the internode. Be aware that if you prune more than half of the hydrangea, you are likely to lose the blooms for that year. The plant will focus on growth and form flower buds for the following year. Therefore, avoid significant pruning in the fall, as it can result in a loss of blooms in the subsequent year.

When to cut to the ground level?

Cutting a hydrangea to ground level is a more drastic form of pruning, typically done for various reasons that won’t be discussed here. The ideal time for such pruning is in the spring, preferably before the leaves start to form. Early March is generally the best time for this task.

It’s important to note that fully pruning a hydrangea in this manner means you will not see any flowers for the current year. The plant will spend the season growing new stems, with blooms returning only the following year.

Another suitable period for this kind of pruning is the early autumn. However, if you choose to prune at this time, be aware that the hydrangea will not flower in the next year. The appropriate timeframe for autumn pruning is from early September to late October.

While complete pruning of hydrangeas is not generally recommended by experienced gardeners, if it becomes necessary, it should be done correctly. When pruning to ground level, cut the stems about 2 inches above the ground to avoid damaging the crown, which could lead to rot.

For this task, use strong, high-quality bypass loppers. Always disinfect your tools before and after use to prevent the spread of disease.

When to prune deadwood?

Pruning deadwood is a crucial task for maintaining the health and appearance of plants, and it can be done throughout most of the year, with winter being the exception. Branches may become damaged or broken due to various factors, including snow weight or disease, particularly in young stems often affected in spring.

The removal of deadwood not only enhances the plant’s appearance but also makes room for new growth. Unlike other seasons where the plant can heal pruning wounds effectively, winter is less ideal because the plant is dormant, increasing the risk of wood rot at the cut sites.

When pruning, it’s important to completely remove the deadwood, and it’s acceptable to cut into the living wood slightly. Over time, the plant will naturally heal these wounds. Cuts should be made at a 45-degree angle to the stem, which helps in water drainage from the wound, reducing the likelihood of rot.

The right tools are essential for effective pruning. For larger branches, a bypass lopper is recommended, while pruning shears are better suited for smaller branches. Before beginning the pruning process, ensure that the tools are sharpened and cleaned to promote healthy cuts and prevent the spread of disease.

Type of pruning When to prune
Deadheading After blooming
Pruning for shape Spring
Cut to the ground level Spring, Autumn
Removing deadwood In any time except winter

After pruning

Proper care following the pruning of hydrangeas is essential and as important as the timing of the pruning itself. Firstly, it’s crucial to treat the hydrangeas with a fungicide solution. This step helps prevent bacteria and fungal spores from infecting the plant through the fresh pruning wounds, which could lead to illness or even loss of the plant.

Secondly, appropriate watering is vital. Hydrangeas have a high demand for moisture due to their large leaves, which lead to significant water evaporation. Insufficient watering can result in yellowing foliage. Post-pruning, hydrangeas’ water needs might decrease initially, but as new growth emerges, their moisture requirements will increase.

Water the hydrangeas as necessary, which could mean daily watering during hot periods. The goal is to keep the soil around the bush consistently moist without over-saturating it.

In addition to watering, hydrangeas need extra nutrients to recover from pruning. Start by applying a liquid fertilizer immediately after pruning to encourage growth. Follow this with a slow-release fertilizer, choosing products with a standard NPK (Nitrogen, Phosphorus, Potassium) formula, readily available in stores. These fertilizers will help the plant regain strength and promote healthy development after pruning.