How Do You Prune Hydrangeas for Healthier Growth?

Design and InstallationGarden Caregarden TriviaIndoor plantsPlant Health CareUncategorized
Written By Peter Morris

Well… that depends on which type it is!

close-up of hydrangea plant being pruned

Reasons to prune

To influence their shape either because they are overgrown or leggy.

Change their natural habit.

Influence the direction of its growth

Rejuvenate old wood

Improve their flowering and fruiting

Enhance its air circulation

Produce more foliage

Keep an artificial shape (HEDGES, ESPALIERS, TOPIARIES, COPPICES) 

The big prune picture

Understanding what it is you want to achieve is the basis for pruning. This understanding comes from the interaction between your goals and the natural habit of the plants. Both of these will influence your pruning.

Pruning with scant regards to the growth and flowering cycles, or natural habit or shape of plants is inviting failure. You should familiarize yourself with all of the aspects of a plants natural habit before beginning. 

After the prune

When you prune, once quiet buds begin to swell and burst into new shoots. The closer to the pruned cut the more buds will swell. The greater the number of stems cut, the greater the number of buds that swell.

The larger the number of leaves lost per stem, the farther down the stem the buds will swell, and in greater numbers. 

multiple sprouts emerging from tree trunk after hard pruning

Multiple sprouts on trunk is an after effect of pruning hard

Flower buds

This is the most crucial issue on pruning Hydrangeas. Plants should be pruned to avoid removing flower buds. If you prune before the bloom cycle begins, you will probably remove flower buds and considerably cut into the quantity of blooms that year. 

For some plants it is advisable to prune IMMEDIATELY after blooming. This is because these plants require a longer period of time to produce stems mature enough to bloom. 

hydrangea bud showing early flower development

Hydrangea bud with flower developing inside

Dormant buds

For others, it is best to prune only while they are DORMANT in the Fall or Winter. These plants bloom from new growth in the spring and do not need a long period of stem maturity to form flower buds. 

ormant hydrangea buds on bare branches

immature floral buds are many times sleeping in the buds !

The act of pruning - Basic pruning elements

1. Prune all dead, damaged and dying branches

2. Prune all crossing and touching branches

3. Prune anything that is not radiating from the center outward

4. Prune the remaining for balance i.e.., make the previous cuts harmoniously blend together or balance.

"Balancing" in pruning means you take in consideration all the previous necessary branches you made and now make aesthetic pruning cuts to keep the overall shape symmetrical.

Do not cover or paint the wound as new studies show these invites insects and disease to settle in the moist microenvironment.

Remember to CLEAN the tool you use for cutting before and after use with bleach or alcohol. 

essential pruning tools laid out for gardening

Basic pruning tools

Most commonly used Hydrangeas – and how to prune them.

Hydrangea anomala "petiolaris"

Grows as a climber, not a shrub or tree form. Needs assistance in attaching to a wall or surface the first season.

Prune ONLY immediately after blooming. Remove long shoots back to central leader, 1-2 per season to keep shape. 

climbing hydrangea growing with aerial roots

Climbs using attaching roots that grow from stem

Hydrangea arborescens “Annabelle”

Prune ONLY in Fall, completely down to the ground. Does not form a tree but in fact a low floppy shrub with hollow stems. Will probably need staking. 

annabelle hydrangea showing hollow stems

Anabelle has hollow stems - not a good choice for a windy spot

Hydrangea macrophylla

Usually forms a stout shrub and is rarely grown as a tree or standard. Prune ONLY immediately after blooming. You will have to decide to skip pruning for a season or two if you want to keep the blooms on the plant the entire season until they become dry and papery. 

classic garden hydrangea blooming in pink

Standard garden Hydrangea - in pink, blue or white

"Endless Summer" is the only exception – it can be pruned of spent flowers in mid-season and will rebloom again that same season. Tends to be a softer stem and more droopy than upright. 

endless summer hydrangea blooming in vibrant blue

H. M. Endless Summer - blue as the sky !

Hydrangea paniculata

These are cone shaped flowers in many shades of white and green. Prune in Fall or very early Spring after buds swell but before buds break. Shrubs can also be pruned back completely to ground level in Fall as it blooms on new growth only.  

Tree shape should be pruned back to the same point every year to promote strong lower supporting branches. This plant is a good choice for pollarding or for a coppice. 

limelight hydrangea with cone-shaped green flowers

"Limelight" variety

Blush of pink Hydrangea Pee Gee is always a favorite

Hydrangea quercifolia

These are usually only available as a shrub or bush, rarely in standard or tree form. Prune ONLY immediately after blooming. Does not require a lot of pruning as it is a slow grower. 

pink-tinted pee gee hydrangea in full bloom

Oak leaf hydrangea tend to prefer a secluded and somewhat shady spot

Hydrangea serrata

Lace cap hydrangea are usually only available as a shrub or bush, rarely in standard or tree form. Comes in many varieties and colors from pale white to blue and pink. Prune ONLY immediately after blooming. Does not need to be pruned very often as it is a slow grower.

oakleaf hydrangea growing in a shaded garden

love the lace cap hydrangeas !

Need something pruned ?

Call us - we know how !  

PLANT SPECIALISTS

GREENING NEW YORK FOR OVER 53 YEARS !

Article written by our Staff Horticulturist, Peter B Morris, BSc, MSc, MBA

All photographs used with permission @SHUTTERSTOCK

Peter Morris

Peter was born and raised on a beautiful green island in the midst of a tropical rainforest. He was introduced into the world of plants at the age of six when his grandmother, an avid Spanish gardener herself, asked him to help her grow seeds for her pepper garden. He was hooked! By the time he was a teen, he had his own rose and orchid collection numbering in the hundreds. Botany was in his blood, and that is what he set out to study.

His passion brought him to NY in the late seventies to further his education. His tenacity allowed him to work full time at Plant Specialists while he completed a MS in Plant Biology. As a manager at the time he felt unsatisfied with his knowledge of business and business processes. Peter felt compelled to learn, so he then pursued and completed an MBA in Quality Management within a few short years.

Peter’s other passion is teaching. His natural ability is quickly consumed by our staff in all subjects in Botany, Horticulture, and Landscaping. He created an immense reference library of more than 3,500 plants providing an invaluable resource for our staff.

Peter’s breadth of knowledge and wisdom allows him to effectively diagnose the needs of plants. Sometimes just by walking into a garden he can create a prescription that fixes even the hardest issue. He is our Staff Botanist, Diagnostician, and all around Mentor. Recently, he has put his immense knowledge and skills into developing a new department that focuses on Plant Healthcare. As he puts it, “Magic through Science”. The PHC staff that surround him have avidly consumed his teachings. Substantially developing their own plant wisdom, many have taken on difficult plant health issues with spectacular results.

Plant Healthcare has been an instant success with customers! The proper treatment of insects and diseases including Organic methods has made pest control a necessity for every plant. Correcting hormonal imbalances caused by planting in containers or refurbishing soils leached of nutrients by irrigation systems are big challenges PHC has become quite comfortable addressing. The scientific approach to the complex demands of keeping plants healthy in our harsh city environment has made many a customer say WOW!

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