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Ericaceous plants add bright, bold, and luscious pops of colour all over your garden. Stunning rhododendrons, delicious blueberries, and elegant Japanese maples – all of these plants love acidic soil.
Follow our guide to caring for the lovely ericaceous plants in your garden.
What Are Ericaceous Plants?
Ericaceous plants are plants in the Ericaceae family, such as heathers. In fact. The term Ericaceae is derived from the Latin term for heather and heath – erica.
Ericaceous plants prefer to grow in acid soil and don’t do well when growing in alkaline soil with high pH or lime. Sometimes they’re even called ‘lime haters!’[1] If grown in alkaline soils, they end up suffering from a condition called lime-induced chlorosis, which turns their leaves yellow. They become stunted, fail to flower, and eventually die.
That’s because ericaceous plants need a lot of iron and nutrients to thrive. However, soils with a high pH cause these nutrients to become insoluble, which means that ericaceous plants are unable to absorb them.
You can correct for your soil’s alkalinity so that you can still grow ericaceous plants in an otherwise non-acidic bed. Dig a large hole in your flowerbed and line it with plastic sheeting that includes some drainage holes. Fill the hole with ericaceous compost or lime-free soil. While this may work in some cases, it often fails. You’ll have more luck growing ericaceous plants in a solely acidic bed.
What Is Ericaceous Compost?
Ericaceous compost is compost designed explicitly for growing acid-loving plants, such as camellias, heather, and azaleas.[2]
The benefits of ericaceous soil:
- Excellent for pot plants
- Acid-loving plants will thrive and flourish in this new environment
- As long as your soil includes a lot of nutrients, you won’t need to feed your plants often
- Holds onto moisture for a long time
- You can make an ericaceous soil mix yourself easily
How to make ericaceous compost:[3]
- Begin by laying down 15 – 20 cm of organic material. To up the acid, make sure to use coffee grounds, oak leaves, and pine needles. Eventually, all compost become alkaline, so to keep things as acid as possible for the longest time, use plenty of pine needles and boughs.
- Calculate the compost pile surface area, and then add 1 cup of dry garden fertilizer (ideally one designed for acid-loving plants) per square foot.
- Add 3 – 5 cm of garden soil over the surface to speed up the decomposition. You can also use finished compost. Alternate layers with plenty of water until your compost heap is nearly 2 metres tall.
Benefits of Growing Ericaceous Plants in Containers
As your garden beds may be too alkaline for their taste, you may have more success growing ericaceous plants in large pots. Not only does this allow you to grow them in the acidic soil they prefer, but you can also place them in the perfect location for the right amount of sun and shade. Your containers should be equipped with an adequate drainage hole and kept at least 15 – 20 cm above any surrounding soil to prevent alkaline water from seeping inside.
Tips for Planting Ericaceous Plants
Check out these useful tips for planting and caring for your ericaceous plants.[4]
They like the shade
Most ericaceous plants do best in dappled shade, making them ideal for a North facing border. They will do well in sunny gardens providing you keep the soil moist.
They are usually hardy
Most acid-loving plants are hardy, but those that produce spring foliage tend to be slightly tender. Keep them in a southerly or westerly aspect, protected from cold winds and bright sun.
They are surface rooting
Ericaceous plants have fine roots, so be careful when transplanting them. To transplant, work ericaceous compost into the soil to create a friable texture, and then carefully transplant into an area 6 times larger than the pot size.
Do not plant them too deep
Cover with only the thinnest layer of soil. If replanting a larger plant, consider tying them to a stake.
Add an annual mulch
Spread a mulch of peat, pine needles (for acid) and leaf mould across the surface, 15 cm from the base of the plant.
Watch out for aphids
Ericaceous plants don’t attract too many pests, except for aphids. Use a regular systemic insecticide to ward them off. In rare cases, vine weevil grubs will attack the roots, so you may also need to apply a weevil killer.
Feeding Tips
Check out these feeding tips to keep your plants looking their best.
Fertilizer is crucial
Keep your ericaceous plants happy and gorgeous by feeding them regularly with fertilizer.
Use specific ericaceous feed
Some plants will thrive with a general-purpose feed, but ericaceous plants will do a lot better if you use specific ericaceous feed. It contains the nutrients necessary to prevent yellow leaves and keep your foliage leafy and green, and your flowers bright and plentiful.
Use a continuous release feed
If you don’t have tons of time to monitor your ericaceous plants like a hawk, use a continuous release feed instead. They work for up to 6 months with just one application. If you prefer the regular routine of feeding your plants, liquid feeds are also a good idea.
Make sure you feed them well in the spring and summer
Many flowering ericaceous plants, such as azaleas, camellias, and rhododendrons, set their buds from June to August. Keep them well-fed in spring and during these summer months.
Watering Tips
Follow these tips to help your ericaceous plants thrive.[5]
Water them well
Most ericaceous plants have shallow roots that can dry out quickly in the sun and heat. Keep your soil moist, especially during the summer when the flower buds set. Water weekly in the dry seasons, and mulch regularly to keep things moist.
Water with rainwater
Collect and use your rainwater to save money and go easy on the environment. However, when rainwater runs out, you can use tap water. Don’t make a long-term habit of this, as it will encourage chlorosis, which yellows the leaves.
Use lime-free mulch
Mulching your ericaceous plants helps to keep the soil moist. Add lots of composted pine needles to lower the pH and maintain the acidity that ericaceous plants love.
Types of Ericaceous Plants
No matter what your preference or colour scheme, there is an ericaceous plant out there perfect for your garden. Relax on your chaise or your teak benches while you admire the results of your labour – spectacular rhododendrons, fragrant California lilac, and colourful camellias.[6]
Bilberries (Vaccinium myrtillus)
Related to the American blueberry plant, bilberries are blue-black berries that fruit in the summer. The shrub grows on moors and in woodlands, and blooms with tubular white flowers.
Japanese anemones
A pretty plant that will grow anywhere except for waterlogged soil. The cream and pink flowers look lovely in any setting.
Trillium erectum
Known for vibrant magenta flowers, trillium blooms also come in white, yellow, and pale purple.
California Lilac (Ceanothus)
Known for its gorgeous perfume, California lilac shrubs grow well in the sun. Their purple blooms and glossy dark green leaves will elevate any garden.
Magnolias (Magnolia Grandiflora)
Magnolias love acidic soil, and delight gardeners all over the world. Their lovely pink flowers bloom in early spring, doing well in both sun and partial shade.
Lilyturf (Liriope muscari)
Lilyturf is a trim and tidy evergreen perennial with prolific blue flowers, often mistaken for hyacinth.
Summer Heather (Calluna vulgaris)
Summer heather adds a gorgeous explosion of pink and purple to your garden in the warmer months. This low growing heather flowers from the late summer months to late autumn.
Camellia (Camellia Japonica)
Camellias do well in acidic soil and are beloved for their gorgeous colourful flowers.
Acid-loving plants
These plants are not technically ericaceous, but they still love acidic soil. Why not try growing these acid-lovers?
- Raspberries
- Acer (Japanese Maple)
- Magnolia (except x loebneriand M. stellata)
- Skimmia
With just a few extra steps, you can help the ericaceous plants thrive and bloom in your garden, adding colour and enchantment. Happy gardening!
Reference list
BBC Gardeners’ World Magazine (2020). 10 plants for acid soils. [online] BBC Gardeners’ World Magazine. Available at: https://www.gardenersworld.com/plants/10-plants-for-acid-soils/ [Accessed 21 Nov. 2020].
Briggs, C. (2019). Ericaceous Compost – Acidic Soil Growing Guide | UpGardener. [online] Up Gardener. Available at: https://upgardener.co.uk/ericaceous-compost/ [Accessed 21 Nov. 2020].
Cartwright, B. (2016). How to grow ericaceous plants. [online] Ashwood Nurseries. Available at: https://www.ashwoodnurseries.com/gardeners-corner/nursery-notes/grow-ericaceous-plants/ [Accessed 21 Nov. 2020].
Dyer, M. (2020). What Is Ericaceous Compost: Information and Plants for Acidic Compost. [online] www.gardeningknowhow.com. Available at: https://www.gardeningknowhow.com/composting/basics/ericaceous-compost-info.htm [Accessed 21 Nov. 2020].
Love the Garden (2017). Ericaceous lime hating plants. [online] Love the Garden. Available at: https://www.lovethegarden.com/uk-en/article/ericaceous-lime-hating-plants#:~:text=What%20are%20ericaceous%20plants%3F [Accessed 21 Nov. 2020].
Royal Horticultural Society (2019). Water: using softened and other types / RHS Gardening. [online] Rhs.org.uk. Available at: https://www.rhs.org.uk/advice/profile?pid=691 [Accessed 19 Mar. 2019].
[1] https://www.lovethegarden.com/uk-en/article/ericaceous-lime-hating-plants#:~:text=What%20are%20ericaceous%20plants%3F
[2] https://upgardener.co.uk/ericaceous-compost/
[3] https://www.gardeningknowhow.com/composting/basics/ericaceous-compost-info.htm
[4] https://www.ashwoodnurseries.com/gardeners-corner/nursery-notes/grow-ericaceous-plants/
[5] https://www.rhs.org.uk/advice/profile?pid=691
[6] https://www.gardenersworld.com/plants/10-plants-for-acid-soils/
Anna is the marketing and office manager for Garden Benches – a premium supplier of high-quality wooden benches and other outdoor furniture.
