The Worst Mistakes for Pruning Hydrangeas

Hydrangeas are a beloved feature in many Australian gardens, providing lush foliage and stunning blooms. However, improper pruning can turn these beautiful plants into a source of frustration. 

Avoiding common pruning mistakes is essential to keeping your hydrangeas healthy and vibrant. 

Let’s dive into the most frequent errors and how to steer clear of them, ensuring your hydrangeas thrive and dazzle year after year.

Mistake: Not Removing Spent Blooms

Failing to remove spent blooms or doing it too late in the season can hinder new growth and reduce next year’s blooms.

Correct Approach

Deadhead hydrangeas during the growing season. Remove spent flowers at any time during the year, even in summer.

Cut just below the spent flower head and above a pair of plump leaf buds. This encourages new growth and additional blooms.

Mistake: Heavy Pruning in Winter

Pruning too heavily in winter can damage the plant and reduce its blooming potential.

Correct Approach

Winter is the perfect time for a harder prune, but don’t take off more than one-third of the shrub. Cut stems down to a pair of plump leaf buds.

For complete rejuvenation, cut back further to just above ground level (only applicable to certain varieties).

Mistake: Hydrangeas Are Not All the Same

Pruning hydrangeas can seem confusing, as there isn’t a ‘one size fits all’ approach that covers every variety.

Correct Approach

Determine which variety you are growing to guarantee the best blooms.

Bigleaf, oakleaf, and mountain hydrangeas flower on old wood, while panicle and smooth hydrangeas flower on new wood.

Climbing hydrangeas bloom on old wood but need to be pruned differently.

Mistake: Pruning Bigleaf Hydrangeas in Winter

Bigleaf hydrangeas bloom on the previous year’s growth. Pruning them in winter will remove the buds needed for the next summer’s blooms.

Correct Approach

Prune bigleaf hydrangeas during their active growing season in summer, immediately after flowering. Cut back spent blooms and limit pruning to one-third of the stems that have just flowered.

For newer cultivars that bloom on both old and new wood, winter pruning is acceptable.

Mistake: Pruning Oakleaf Hydrangeas in Winter

Oakleaf hydrangeas also bloom on old wood. Winter pruning will remove the buds and reduce blooms.

Correct Approach

Deadhead oakleaf hydrangeas in summer once the blooms have finished.

Cut the stems to just above a pair of plump buds. This allows new stems to grow before the colder weather arrives, ensuring blooms the following summer.

Mistake: Light Pruning of Panicle Hydrangeas

Light pruning of panicle hydrangeas won’t stimulate enough new growth and can result in fewer flowers.

Correct Approach

Prune panicle hydrangeas in winter or early spring before new growth starts. Cut back stems to just above a pair of healthy buds to encourage vigorous new growth and abundant blooms.

Mistake: Neglecting Hard Pruning of Smooth Hydrangeas

Neglecting hard pruning of smooth hydrangeas can result in a tangled, unruly shrub with fewer flowers.

Correct Approach

Hard prune smooth hydrangeas in late winter or early spring, cutting stems back to ground level. This promotes strong new growth and a full, flowering plant in summer.

For a larger shrub, leave some stems longer while maintaining overall shape.

Mistake: Using Blunt Tools

Using blunt or dirty tools can crush and tear the plant’s tissues, causing ragged cuts that take longer to heal and make the plant more susceptible to diseases.

Correct Approach

Always use sharp, clean pruning shears. Clean and sharpen your tools regularly to ensure precise cuts. This will help your hydrangeas heal quickly and reduce the risk of infection.

Mistake: Pruning at the Wrong Angle

Cutting stems straight across leaves the plant more vulnerable to fungal infection because water can collect on the wound.

Correct Approach

Cut stems at a 45-degree angle, positioning your pruning shears 6 mm above a bud. This allows water to run off the cut, reducing the risk of fungal infection.

Conclusion

Ensuring your hydrangeas remain a stunning focal point in your garden involves avoiding these common pruning mistakes.

Understanding the specific needs of your hydrangea species and timing your pruning correctly can make all the difference. Happy gardening!