Pieris Japonica Overview
|Official Plant Name||Pieris Japonica|
|Common Name(s)||Japanese Pieris|
|Foliage||Evergreen, leathery dark green leaves, often different and brightly hued when young|
|When To Sow||February, March, September, October|
|Flowering Months||May, June|
|When To Prune||June|
Full Sun or Partial Shade
2.5 – 4M
2.5 – 4M
May – June
Moist but well drained
This hardy, evergreen shrub is popular amongst gardeners, thanks to its elegant and colourful blooms.
Pieris Japonica draws on soft whites, vibrant pinks, and striking reds to deliver new and exciting colour combinations year-round. It really does have a lot to offer gardeners of all abilities.
Pieris works particularly well as part of a shrub display, or in areas of your garden with a woodland feel. The plant has confidence and poise to work equally well as a part of a group of shrubs, or as a standalone.
We’ve written this guide to tell you everything you need to know about Pieris Japonica. After reading, you’ll be confident in choosing the right variety for your garden, and in helping it to thrive.
What is Pieris Japonica?
It’s a type of shrub from the heather family that originally hails from Asia, and the drooping bundles of lantern-shaped flowers that appear in spring definitely evoke the essence of the orient. Although the floral bloom could be considered short – just two or three weeks – Pieris Japonica punches above its weight aesthetically throughout the year.
Although Pieris Japonica is the most common name, you may also hear the plant referred to as Japanese Andromeda, Japanese Pieris, or even Dwarf Lily-of-the-Valley Shrub. The latter is not to be confused with another Lily-of-the-Valley, Convallaria Majalis, which looks quite different!
Japonica is the most popular of seven species of Pieris. Others include Cubensis, Floribunda, Formosa, Nana, Phillyreifolia, and Swinhoei. This guide covers plants in the Japonica species, but the others also have a lot to offer.
What types of Pieris Japonica are there?
Search for ‘Pieris Japonica’ in the Royal Horticultural Society’s plant database, and you’ll be greeted by over one hundred results. That’s a lot of Japonica!
Instead of listing them all here, we’ll showcase some of the most popular. We’ve prioritised varieties that have been awarded the RHS Award of Garden Merit – a commendation given to plants that are particularly well-suited to growing in typical UK conditions.
All of these varieties have also received the RHS Plants for Pollinators award. This means that they are popular amongst bees, butterflies, and other insects hungry for pollen. If you’re keen to attract such critters to your garden, these varieties are your best bet.
Pieris Japonica ‘Mountain Fire
Perhaps the most popular variety, Mountain Fire boasts rich red leaves which mature into dark green via several attractive intermediary shades. Reaching a maximum height and spread of four metres, this shrub makes a beautiful addition to any garden.
Pieris Japonica ‘Sarabande’
Reading through the list of Pieris Japonica varieties is a precession of elegant, glamorous names, and Sarabande is the perfect embodiment of this. Growing to a slightly smaller size than Mountain Fire, Sarabande has leaves sporting a bronze tinge and eye-catching white flowers.
Pieris Japonica ‘Debutante’
Another inherently elegant name, Debutante refers to the first appearance in fashionable society of an upper-class young lady. It’s not hard to see where the name came from. This variety is petite when compared to others in this list, and is characterised by bold, clean white flowers.
Pieris Japonica ‘Pink Delight’
As you’ll probably guess from the name, Pink Delight brings a gentle pink hue to your garden. Another effortless demonstration of the vibrant colour swatches that Pieris Japonica can draw from. In terms of size, this variety sits at the lower end of the spectrum. You can expect a maximum spread of about one and a half metres.
Pieris Japonica ‘Bonfire’
Bonfire brings brick red in its youth, giving way to pale pink and white flowers each spring. This variety can be considered a middle ground between the more vibrant reds and pinks found elsewhere in Pieris Japonica’s colour palette. Bonfire is another petite variety, clocking in at around a metre.
Pieris Japonica ‘Carnaval’
Carnaval riffs on an already familiar theme of green, red, pink, and white. You’ll find bright red leaves with pink edging in spring, followed by white winter buds that flower in spring. You can expect a height of around a metre and a half, and a spread of slightly less.
Pieris Japonica ‘Valley Valentine’
This variety will bring beautiful tumbling tendrils of striking red to your garden. Set against the dark green leaves, it’s hard not to find the colouration mesmerising. Valley Valentine is one of the largest Pieris Japonica varieties: expect it to grow to two and a half metres square.
Pieris Japonica ‘Prelude’
Here we have a compact, predominantly white variety of the Japonica. Although there are a couple of other white varieties in our list already, we’ve included the Prelude because it is just that striking.
As we said at the start of this section, this is just a small selection of Pieris Japonica varieties available. To see more, have a look at the results in the RHS plant database here.
Introducing a Pieris plant into your garden
If one of the varieties in our list has piqued your fancy, you’re probably wondering how best to grow a Pieris Japonica in your garden.
Thankfully this is quite a hardy plant. The RHS has given many varieties a hardiness rating of H5, which means they are “hardy in most places throughout the UK even in severe winters (-15 to -10).”
With that in mind, it’s still essential to ensure you plant out your Japonica in the right soil and light conditions.
What soil does a Pieris need?
All varieties of Pieris Japonica thrive in sandy, loamy soil with some acidity. For optimal growing conditions, the soil should be well-drained with some residual moisture.
This plant will not tolerate alkaline soil, so use nutrients to adjust the soil pH if the area you’re planning on planting into is not acidic enough.
Where to plant your Pieris
These plants will do best in full sun or partial shade and will struggle with no sunlight whatsoever. To give them the best chance at healthy growth, choose a location that is east or west facing to be safe. Some varieties from our list above can handle facing south, but none should be planted in a north-facing direction.
We recommend checking the RHS plants database to find the specific preferences of each variety.
When to plant your Pieris
For the best results, plant your Japonica in spring or autumn.
With a Pieris, you can expect red growth around the leaves in February, followed by the most vibrant period of growth in March. This gives way to flowers – usually white but not always, as we’ve seen above – in April and May. As an evergreen, the leaves will stay on year-round.
Planting out your Pieris
Work a layer of rich compost into the soil to provide nourishment, then plant your Japonica in a hole whose depth matches the extent of the root system. You should leave about two metres between individual shrubs if you are planting more than one at a time.
Keeping the soil moist will help your Japonica to grow at its best. We also recommend fertilising the plant in winter to ensure it gets all the nutrients it needs over winter. The fertiliser you use should be tailored to the requirements of plants that prefer acidic soil.
Ongoing Pieris care
One of the reasons Pieris Japonica is so popular amongst gardeners is the minimal care it requires. If you plant it in the right conditions and keep an eye out for any pests, your shrub will take care of itself. All you need to do is sit back and enjoy the show!
A small caveat: though they are hardy, if extreme frosts are forecast, you should take steps to keep your plant’s roots warm. This is as simple as spreading some straw, pine needles, or similar around its base.
How to prune your Pieris
As implied by the previous section, pruning isn’t required. If you decide to prune for aesthetic reasons, try to do so in late spring after the plant has flowered.
Protecting your Pieris from pests and diseases
Hardy though it may be, Pieris Japonica is not immune from pests and diseases. Although there are no particularly severe threats, it’s always a good idea to keep your eye out for any potential issues. If you see discolouration on the leaves, dead patches, or any other blemishes, your plant may be feeling poorly.
Here’s what to look out for:
Pieris lace bug
This pest can infest certain varieties of Pieris, but not all varieties are equally susceptible. From the list above, Bonfire and Carnaval are considered most at risk.
The lace bug will suck sap from a Pieris plant, leading to pale and mottled leaves. They also leave patches of excrement behind – no prizes for guessing what this brown material is…
A Pieris Japonica will be able to tolerate a small infestation, but you should prune heavily infested ones. A selection of organic and synthetic pesticides can be used to remove infestations, but be careful not to apply them while your plant is flowering. Such chemicals will cause harm to any pollinating insects that visit your garden.
It’s interesting to note that this pest is a relatively recent arrival in the UK, having first been found just over twenty years ago. Since its appearance, it has proved quite prolific, however, and now spans across the whole country.
As with choosing the spot for your plant, we recommend checking the RHS database for specific pest concerns of your selected variety.
The Greek roots of this word paint a stark picture: ‘phyton’ means plant; ‘phthora’, destruction. An infected plant will experience decaying and rotting roots, caused by microscopic organisms.
One of the most significant risk factors for phytophthora is waterlogged soil, which is one of the reasons why well-drained soil is so crucial for Pieris Japonica. In fact, good drainage is the most reliable way to reduce the risk of infection.
Often the symptoms presented are similar to other conditions damaging a plant’s root system, so it can be hard to identify. Sadly, destruction of infected plants is considered to be the best course of action in preventing further spread of infection.
This blight is most likely when your plants are weak or overcrowded. It’s also a risk in humid climates, although sadly that’s not really a problem in the UK!
To reduce the likelihood of leaf spot, remember to plant your Pieris shrubs at least a couple of meters apart. This will give them space to thrive and grow strong.
If you see patches of grey or brown, prune back the infected section and destroy the pruned leaves (note: never compost them!). Keep a careful eye on the new growth that replaces these pruned sections, as this will be more susceptible to leaf spot than strong and established parts of the plant.
Now, over to you!
We’re big fans of Pieris Japonica. It’s an attractive and hardy addition to any garden, and the colour palette drawn upon by the numerous varieties give you a lot to work with. Whether you’re looking for subdued white or bold, vibrant pink, a Japonica could be just the plant for you.
This guide covers everything you need to know to get a plant thriving in your garden, whether you grow it from seed or otherwise. Thanks for reading, and happy gardening!