How & when to prune Hydrangeas: Beginners guide to beautiful blooms

Most gardeners would be hard pushed not to recognise a Hydrangea. The classic ‘Granny’s garden’ shrub with its textured leaves and massive blue, pink, white or mauve flower heads. Hydrangeas give a real show of huge flowers for months during the summer. Their flowers can then be left in situ to fade from their vibrant early summer colours into translucent winter flower heads. The hydrangea is the true workhorse of the garden shrubs and very easy to look through pruning.

Hydrangeas are best suited to dappled or part shade and once established will provide a robust shrub with both detailed foliage and some wonderfully diverse flower heads. These can be left on the plant for months of interest or used as cut flowers or dried for a variety of decorative uses.

• Common Types of Hydrangea for Pruning
• Do I need to prune hydrangeas?
• How to prune a Hydrangea in 3 steps
• Should I mulch my hydrangea?

Common Types of Hydrangea

This guide will help you prune the most common types of Hydrangea. For most Hydrangeas, late Winter & Early Spring is the best time to prune and remove their old seed heads. This is because the faded flowers add winter interest and also offer some frost protection to the shrub.

Each area will differ slightly, but I prune my Hydrangeas late Feb here in the UK. Even though we get frosts in March, my Hydrangeas have already put on new growth in February which is the signal for me to prune them.

Below is a list of when to prune different types of hydrangea. The pruning technique is very similar for all three with the exception of the climbing hydrangea where you just remove the spent flowers and do a light tidy up.

• Hydrangea macrophylla (Mophead or Lacecap late winter prune)
• Hydrangea paniculata (Prune late winter)
• Hydrangea petiolaris (Climbing – Prune directly after flowering in Summer)

Pruning Hydrangeas couldn’t be simpler and this guide is to help you avoid some of the common Hydrangea pruning mistakes and rookie errors. Which will help you get the most out of these lovely shrubs and provide maximum interest throughout the year! If you have species not listed above then a mid Spring prune is the safest bet or seek more specialist advice based on your plant type.

Do I need to prune my hydrangea?

The quick answer is yes over time you will need to prune your hydrangea to help keep it in a neat and tidy shape. If you don’t prune your hydrangeas each year then the old flowers can get tangled with new growth. What you will also find is that over time the hydrangea gets taller and ‘leggier’ as the years go on. Resulting in flowers on the top of the hydrangea plant and then exposed woody bare stems below.

Hydrangeas tend to flower better on newer wood. So by keeping your hydrangeas pruned each year you’re encouraging fresh growth which will bring you vibrant healthy flowers each year. It is easy to tell if your hydrangea needs a prune as the spent flowers will be brown and crispy also the leaves usually fall off during the winter leading to buds in the spring. It is when these buds have emerged that you know it is time to prune your hydrangeas.

How to prune a Hydrangea

Pruning a Hydrangea couldn’t be simpler and requires very little in the way of pruning. All you need is a sharp pair of secateurs and you’re ready to prune. I prune mine here in the UK in late February. It doesn’t take long to prune hydrangeas and there’s very little damage you can do that won’t grow back. So please don’t be put off pruning in the worry you will somehow damage your Hydrangea!

Clean sharp secateurs are essential with pruning and tidying up hydrangeas are no exception. The cleaner the cut the faster the hydrangea will heal and also less disease or potential damage from snagged secateurs.

1.Remove all the dead seed heads

The first step is the remove all of the previous year’s seed heads. I take these back just above the next set of green buds which are emerging. I do this first before thinning or reducing the height of the shrub as it gives me a better view of the overall shrub size and shape. This is turn will allow you to make better pruning decisions for the next few steps. Which means less fuss or concern about what to cut back as you have a clearer view.

The dried seed heads of the hydrangea are now spent. Remove them for a cleaner neater looking hydrangea shrub. You can use them in flower arranging or compost these hydrangea flowers to recycle them.

2.Remove 1/4 of the oldest stems

By removing around 1/4 of the oldest wood/stems you can help keep your Hydrangea productive as energy will then be sent into new fresh growth. Over time older stems will get longer and less productive leading to potential bare patches and less productive displays.

Take these older stems right back to the ground in a clean sharp cut. This will encourage fresh new growth and keep the Hydrangea on its toes to perform!

If your hydrangea shrub is looking congested or very ‘busy’ in the centre its best to thin it out. Congested hydrangeas are more prone to branches rubbing each other, causing damage or getting infected by mildew due to lack of airflow.

3.Thin out any congested branches or damaged stems

Once you’ve removed the flower heads and cleared some of the older stems the next step is to then thin out any congested growth or crossing branches. These will tend to rub and have a higher chance of damage. Also, flowers that may be sent out in these tangled areas may get crushed or become damaged. So it’s best to be brave and remove these branches opting for the stronger of the two when crossing.

Damaged stems may be snapped or may show signs of black die back which both need to be removed. Either cut back to the next healthy bud down or remove to the ground if needed. Don’t panic if you take off too much during the pruning process. Plants are incredibly tough and will always bounce back. A hard prune always gives your plants an added boost during the next growing season! If you don’t prune back damaged wood it can get infected and takes valuable resources from the plant in trying to heal them. Leading to fewer hydrangea flowers and a lacklustre shrub.

Once you’ve finished you should be left with an open airy shrub with plenty of airflow and no crossing stems. The clippings can be composted and your Hydrangea is now in a perfect position to put on gorgeous flowers all summer long!

Because you’ve opened up airflow by pruning your hydrangea you will find it less susceptible to disease and damage throughout the year. This means that your hydrangea will flower more profusely and not have to waste energy on repairing damaged wood. So it really does pay to prune your hydrangeas each year for maximum flowers in your garden each year!

Pruning & Sharpening Garden Guides

Should I mulch my hydrangea?

The next big question is around mulching Hydrangea. Mulching is the act of adding a top layer of organic material such as peat-free compost or well rotten manure on top of the soil around the base of your shrubs. Mulching helps feed your plants slowly over the course of a year, helps retain moisture and also reduce weeds. It’s a really beneficial way to keep your plants healthy.

Hydrangeas are acidic soil loving plants preferring soil PH of 5.5 or lower. There is some debate that lowering the PH of your soil with a pine needle or peat mulch can help turn Hydrangea flowers blue. I see this all the time on social media.

However, this is not an exact science and in my experience, I would just enjoy the colour of hydrangeas you have now. It can often be frustrating and expensive trying to change them leading to disappointment. Afterall keeping non-acidic soil acidic is going to take a lot of mulch and messing around.

If you have questions or pruning comments why not let me know below? You can Tweet, Facebook or Instagram me. You can also follow me on Youtube where I’ve got plenty of garden guide vlogs!

Happy Pruning!