Do hydrangeas need ericaceous compost?

Do hydrangeas need ericaceous compost?

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Hydrangeas can survive in many types of soils, but they need rich nutrients and moist, well-drained soil to do so. But what is all this talk of ericaceous compost?

What is ericaceous soil?

Ericaceous soil or compost is highly acidic, lime free. It is not something appropriate for all plants, as some plants simply cannot tolerate the acidic breakdown. Traditionally, this type of soil was mixed with peat but can be mixed with bark as well.

Figuring out if your hydrangeas need ericaceous compost really depends on the type of hydrangea you have, and whether you are trying to control the flower color.

Consider this: bigleaf hydrangeas are the most common type of hydrangea. They are the shrubs with the big blue or pink blooms with a few pinks and purples thrown in for good measure. What is most interesting about these particular varieties, the mopheads or the lacecaps, is that you can control the color of the blooms by changing the soil ph. Adding compost to alter the pH of the soil will determine the color of the blooms you get. If you want or have blue hydrangeas you need ericaceous compost. For other colours and white normal multi-purpose or shrub compost is fine.

Westland Gro-Sure Ericaceous Compost 10 Litres
Ideal for planting blue hydrangeas
Westland 50L Multi-Purpose Compost with John Innes, Brown
Ideal for planting all hydrangeas in but not blue

Hydrangea care

When you are cultivating these types of hydrangeas, they need an area that is exposed to morning sunlight but shaded in the afternoon. This helps them to retain moisture in the soil. This is also why so many gardeners use them in their shaded border regions of a yard. As mentioned, these shrubs need rich soil that remains moist. Increasing the amount of organic matter will help the roots to conserve moisture at the roots. For lighter soil, ericaceous fertilizers can be added to help feed the hydrangeas.


Not all varieties can change the color of their blooms. Be sure you are growing a bigleaf variety, the hydrangea macrophylla if you are trying to control the color of the blooms but you can’t change white flowers any other colour.

Hydrangea soil pH

You can add ericaceous compost to your soil in order to change the pH of the soil and subsequently, the color of the blooms you see in your garden. Soils that are acidic, with pH of 5.5. or less, full of ample aluminium, will turn blue. Soils that are alkaline, with a high pH and less aluminium will turn pink.

If your soil is neutral, you can also make your flowers blue by adding a blueing agent with aluminum sulphate to your soil.

Vitax 500g Hydrangea Colourant
Ideal feed for blue hydrangeas

The most effective method for potted hydrangeas though is to add ericaceous compost to the potting mix.

The fact that the shrub grows in almost any level of pH is what makes it so reliable. Regardless of your original soil composition, you can still achieve beautiful blooms.

To do this, you should:

  1. Purchase an at home test kit for soil pH.
  2. Administer a test to get a baseline of your existing soil.
  3. Add ericaceous compost or acidifiers to change the acidity.
  4. Regularly re-test to verify that you have the desired pH.
Garden Tutor Soil pH Test Kit (3.5-9 Range) | 100 Soil pH Test Strips
ideal for testing soil ph levels for hydrangeas


Your soil will always return to its natural state. So if you plan to turn the flowers blue on your hydrangeas, be prepared to add ericaceous compost to the soil every year in order to maintain the blue color. Most people have great success when growing them in pots as its easier to control the soil ph and they can be plants in ericaceous compost to start with.

Image by xcoffeeelenax from Pixabay

Last update on 2024-03-17 / Affiliate links / Images from Amazon Product Advertising API

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