CLIMBING HYDRANGEAS (HYDRANGEA PETIOLARIS): HOW TO GROW AND PLANT CARE

While hydrangea shrubs are a part of many people’s gardens, fewer know about the climbing hydrangea, which adds color and interest to any vertical surface, transforming a dull fence or bare obelisk into something amazing when the flowers are in bloom.

It helps that there are many colors to choose from, including purple, pink, white, and blue, matching or contrasting with any garden scheme.

But how do you know if a climbing hydrangea is right for your garden? 

Let’s take a look. 

At A Glance: What You Should Know About Climbing Hydrangeas

There are several plants that go by the name climbing hydrangea, including Decumaria barbara, Hydrangea anomala, Hydrangea hydrangeoides, Hydrangea petiolaris, and Pileostegia viburnoides. 

The one we’re focusing on is Hydrangea petiolaris, which is a beautiful deciduous vine, hailing from Siberia, the forests of Japan, and the Korean peninsula. 

It’s grown in many parts of the world, particularly in temperate regions that get warm summers and colder winters, providing seas of color, and attracting plenty of pollinators.

It can grow up to 50 feet tall in its natural habitat, reaching 6 feet wide. It produces aerial roots on the stems that allow the plant to anchor to vertical surfaces such as trees and rock faces, or in the garden, trellises, walls, and pretty much anything else you can think of.

It also has another method of climbing, where it produces twining vines that wind around any structure to help support the plant. 

This is unusual for a climbing plant. What’s even more unusual is that this particular climber is slow-growing, which makes it perfect for low-maintenance vertical planting.

Many climbers are invasive plants that get out of hand quickly if not controlled properly, and while a climbing hydrangea will take a while to grow wild, it will get there unless you keep an eye on it.

The climbing hydrangea produces large clusters of flowers, and from a distance, these look like a single flower head. 

To add to the plant’s beauty, the leaves are heart-shaped, making a great display even when it’s not in the flowering season.

Unlike most hydrangea shrubs, the climbing hydrangea loses its leaves during fall, so it may be worth growing another climber alongside it, one that is evergreen, or even flowers during the winter, so that the surface isn’t completely bare.

Where You Can Grow Climbing Hydrangeas

Climbing hydrangeas need support, and there are many ways to support them. You can even get creative with this, growing them up statues or salvaged structures to clamber up. 

The possibilities are endless, provided that you give a climbing hydrangea the right growing conditions, and if the structure isn’t very tall, you’ll need to keep pruning the plant to stop it from toppling it over.

Fences

Climbing hydrangeas are perfect for fences that could do with a little more love and color. 

Most types of fence are robust enough to support a climbing hydrangea, but it helps to put some rungs in there, and garden wire or string to create some more support where needed.

You can then thread the vines up the support, but you won’t need to do this very often at all.

Depending on the size of your fence and the growing conditions, a climbing hydrangea may outgrow it, in which case it might be worth trimming it back occasionally, to stop the plant from pulling down the fence with its weight. 

A climbing hydrangea can also act as a privacy screen when the plant is in its growing season, though you will have to replace it with something else come winter time, perhaps something like a winter-flowering clematis.

Trellises

Trellises are popular with many gardeners, and it’s not difficult to see why. There are many designs and sizes that will suit nearly any garden you can imagine, and it’s hard to make them look out of place once the plants have settled in.

Trellises are a good option because you don’t need to add any additional rungs or supports, and the plants will largely attach themselves to the trellis without any help.

However, it’s important to note that climbing hydrangeas can get heavy quickly as they get bigger, so you will need a trellis that can take the weight as the plant gets bigger. 

You could attach a trellis to a stronger structure, such as a garden wall or an exterior wall for extra support.

Exterior Walls

Climbing hydrangeas are handsome plants to train up any exterior wall, thanks to their beautiful flowers and aerial roots which will attach themselves to the walls.

It’s important to consider where the wall faces, however. These climbers don’t like baking sunlight all day when up against a wall, as this will fry them, and given enough time, the sunlight will kill the plants. 

Consider training them up a Northern or Eastern-facing wall, which will give them plenty of sunlight without scorching the plants.

However, it’s important to make sure that with any climbing plant, it doesn’t get anywhere that it can cause damage. 

Prune away any vines that get too close to your gutters, roof, windows, vents, or anywhere else that you don’t want them growing in.

Another way of protecting your exterior walls is to fix trellises to them, so that the plant is growing against the trellis and not the walls themselves.

Trees

Trees make a fantastic support for climbing hydrangeas, as long as the tree is large, strong, healthy, and has a good root system to support itself and the extra weight of a climbing hydrangea.

Like with any climbing plant, however, there is a point where the climber will cause damage to the support if not managed properly. 

Some climbers have been known to bring down trees under their own weight, and this is something you want to avoid at all costs!

Make sure that the vine doesn’t reach the branches of the tree, as it can compete with the tree for light, and weaken it enough to eventually topple the tree.

Prune the climbing hydrangea before it gets to that point, and come summer, you will have a magical display of flowers.

Pergolas

If you have a pergola or a summer house in your garden, why not try growing a climbing hydrangea up it? 

Many pergolas are designed to support climbers with slats for the plants to grab onto.

It also helps that these structures offer more support than fences and trellises, and as long as there aren’t any structural problems with the pergola, it will support your climbing hydrangea just fine.

It’s worth taking a quick look at your pergola before you attempt to grow a climber up it, especially if it’s had something climbing up it before. 

Remove any rotten or damaged wood, and replace them with fresh wood that’s been protected with varnish and paint, so you stop any problems before they can start. 

Ground Cover/As A Shrub

If you don’t have any reasonable support you can grow a climbing hydrangea up, that’s not to say you can’t grow a climbing hydrangea at all.

There are two other ways you can grow them without vertical support: as ground cover, or as a normal shrub. If you don’t provide the plant with any support, it will simply grow upward until it’s about four foot tall, forming a shrub with a sort of arching growth habit.

If you want to keep it as a shrub, make sure you prune it at least once a year, otherwise it will grow into a ground cover, attaching itself to the soil instead.

If you’d like it to grow as a ground cover from the get go, you can use tie-ins to make sure that the plant grows horizontally instead of vertically, but you will still need to keep an eye on it to see if it needs pruning, and stop it from blocking the light for other plants. 

How To Make Sure Climbing Hydrangeas Thrive In Your Garden

Climbing hydrangeas are not difficult plants to grow, but you will need to be patient with them. 

These plants don’t flower until the plant is mature, taking between 3 and 7 years to do so, but you can buy an established plant to speed up this process.

The reason why they don’t flower for so long is because the plants need to put all their energy into growing strong stems, roots, and leaves, so they can harvest enough light and nutrients to make the flowers.

Once the climbing hydrangea has matured, it will bloom reliably every year, for many years to come. The wait is certainly worth it. 

Here’s how to get the best out of these gorgeous plants.

Consider The Climate

One thing to note is that climbing hydrangeas need certain climate conditions to thrive. 

They’re classed as hardy in USDA zones 5, 6, and 7, and prefer cooler climates that don’t get fiercely hot often, as the plants are prone to scorching.

The climbing hydrangea should withstand some frost without issue, but the frosts are too severe, or come too quickly, they may stop the plant from blooming the following year. 

That doesn’t mean you can’t grow them in warmer climates, but they will need slightly different conditions. You may want to put these plants in a shadier position, and up the watering schedule.

Sunlight And Position

Climbing hydrangeas like partial sunlight, with four hours of direct sunlight or less. This stops the plant from wilting, as it is sensitive to direct sun, especially in warmer climates.

In very warm areas where the sun is particularly fierce, you’ll want to make sure that the plant is in a well-shaded position, somewhere that gets around two hours or so of direct sunlight, but no more. This will stop the plant from losing moisture too quickly, which will damage the plant.

Soil Requirements

Climbing hydrangeas like soil that is slightly acidic, with enough drainage to stop the roots from sitting in saturated soil for too long.

But there is a balance to strike, as the soil needs to stay somewhat moist to sustain the plant’s growth. 

A good way of keeping some moisture within the soil is to mulch the top layer of the compost thinly, and this will stop too much moisture from evaporating.

When To Feed A Climbing Hydrangea

You’ll only need to feed a climbing hydrangea when it’s the beginning of the flowering season, as this will help give the plant a boost when it’s putting so much energy into flower production.

If the plant looks a little raggy after the flowering season, it’s worth giving them a feed at that point, too. This will help give the plant a bit of a boost before winter.

The only fertilizer that you might need before the flowering season is a pH balancer if the soil isn’t acidic enough to begin with, but trying to change the pH of your soil is a difficult and often thankless task.

When And How To Prune A Climbing Hydrangea

With most climbing plants, it’s important to keep on top of the growth before things get out of hand, and the climbing hydrangea is no exception.

However, before the plant starts flowering, you rarely need to prune it at all. Make sure that you keep winding the vines into the support you want them to climb, and keep an eye on them.

Once the climbing hydrangea has started blooming, it will grow more quickly, and you will want to keep on top of any stray vines, making sure the plant isn’t growing anywhere you don’t want it.

This is extremely important if you’re growing a climbing hydrangea up the side of your house, for example. Keep the vine away from exposed parts, such as gutters, vents, and windows.

How Tall Can Climbing Hydrangeas Get?

While climbing hydrangeas are slow to get started, don’t underestimate these plants. They can reach heights of 50 feet or even higher, provided that there is something equally tall to support these climbers.

Even when grown as a ground cover, this plant can get very long if you don’t prune it. This makes for a great sprawling look, while suppressing leaves.

If you don’t want your climbing hydrangea to get this tall, or you don’t want it to cover an entire bed, keep on top of the pruning, and this will go a long way in stopping your climbing hydrangea from going wild.

Things To Consider Before Growing Climbing Hydrangeas

While climbing hydrangeas look great in any environment, there are a few things you should think about before buying one and picking up a spade.

Potential Damage To The Environment

Climbing hydrangeas, although they are slow-growing, can damage the surface they clamber up if not managed properly.

This is especially true if the support is flimsy to begin with, such as a small fence or trellis that isn’t designed to hold a lot of weight. 

You also have to be mindful of training climbers up the exterior walls of your house. The aerial roots will attach and cling themselves to any surface, including gutters and vents, and this can cause problems or even damage.

Some climbers such as ivy have been known to grow into mortar and even into the brickwork itself, causing structural damage!

Keeping on top of pruning, and even growing your climbing hydrangea up a trellis on an exterior wall can help stop these issues.

It’s also important to think about if you want the climbing hydrangea there forever. Removing it will leave stains and marks that you will need to paint over, and you need to ask yourself if that’s something you would mind sorting, or not. 

Leaf Scorching In Bright Lights

While climbing hydrangeas are resilient, one thing they cannot stand for long is prolonged periods of direct sunlight. 

It’s not something they have adapted to, so it can cause scorching, wilting, and even the death of the plant if you do nothing.

But this is easily prevented, however. Simply position them somewhere in your garden that only gets partial sunlight, between two and four hours of direct sunlight a day. 

If you can, avoid placing them somewhere afternoon sun hits, as this is particularly strong. Otherwise, you can provide shade in the form of other plants or trees, provided that they are tall enough, and will stay tall enough.

Vulnerability To Disease

It’s worth knowing that climbing hydrangeas are vulnerable to disease, so you will want to keep this in mind when it comes to choosing the best place in your garden for them.

In particular, mildew and rust take hold of a climbing hydrangea very quickly. Healthy plants do not have a problem with fungal diseases such as these, but growing a plant in the wrong conditions quickly leads to problems.

Too much watering combined with a shady area will inevitably lead to mildew, as it means there is too much moisture and not enough air circulation around the plant. 

Trimming off affected areas of the plant will go a long way to help combat mildew, as well as scaling back the watering. 

Don’t forget, plants in shade don’t need nearly as much water as those that are in full sunlight, and they are more vulnerable to fungal diseases caused by too much moisture because the sunlight cannot evaporate the extra water.

If you do spot signs of disease such as these, give the plant a prune, making sure to disinfect the loppers afterward, so it can’t spread to other plants.

Final Thoughts

Climbing hydrangeas are suitable for many vertical surfaces, as long as you keep on top of the growth, making sure that they don’t climb anywhere you don’t want them to.

This is easily done when you consider that the plant is quite slow-growing, making it a great plant to grow up exterior walls or garden fences and obelisks.

Another thing to watch out for is making sure that the plant gets enough sunlight, but not too much that it will cause scorching. 

There is a balancing act to getting the conditions right for any plant, but the best way of learning is to simply buy one and try it out.

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