Garden Questions: Do Hydrangeas Need Ericaceous Soil?

Going to plant hydrangeas and are wondering how to do best by them? You need to provide them with nutrient-rich, moist, and well-drained soil to flourish. And you’ve probably already heard about fertilisers, plant food and wood ash, but there’s one more thing that you probably know of. With all this talk of ericaceous soil, you must be wondering what it is and how it will benefit your precious hydrangeas.

Some blue hydrangeas in a wonderful garden

Believe it or not, we were also faced with a similar dilemma while planting hydrangeas. We also thought – what on earth is it and what does it do? To answer your queries and to make planting hydrangeas an easy job for you, we have put together this compact yet comprehensive article for you! Without further ado, let’s get started!

What is ericaceous soil?

Let’s get right to it – It is highly acidic, lime-free soil. It is not suitable for all plants though. Ericaceous word related to the family of plants “Ericaceae”. The plants in this family can grow in acidic soil only. This means that these plants would flourish in acidic compost. The compost will act as a nutritious supplement to aid their growth. Ericaceous-plants are also known as lime-hating plants. This means that they don’t grow well in alkaline soils.

Figuring out whether your hydrangeas actually need this kind of soil is dependent on the type of plant you are growing. Moreover, it also depends on whether you are trying to control the flower’s colour or notThe very interesting thing about hydrangeas is that you can control their colour by altering the soil’s pH. Generally, if you want blue hydrangeas, you will need ericaceous (that’s a tough word) compost

What are hydrangeas and what are the different types?

Hydrangea offers a lot of varieties when it comes to flowers, foliage, and growth characteristics. These versatile plants are found in every shape & size imaginable. Many of the hydrangeas grow to become medium-sized, attractive shrubs that look stunning in gardens but a few of them are compact and can be grown in containers. From beautiful azaleas and camellias to pink hydrangeas & rhododendrons, you will find several hydrangea varieties. Moreover, a few of them become climbers as well even in harsh growing seasons. Let’s take a look at a few types and varieties of hydrangeas that are readily available.

1. Bigleaf hydrangea

Bigleaf hydrangea – also known as hydrangea macrophylla is the most popular species of hydrangeas. They change the flower colour based on how much acidic the soil is. Many of you would recognize them because of their large flower heads that are pink, blue, purple, etc. 

A bigleaf hydrangea in pink colour that flourishes

Generally, lace caps and mop heads have thick, crisp leaves which are heart-shaped and often shiny. The first famous type of bigleaf hydrangea is the mophead hydrangea variety that has full orbs of blossoms. The other type of bigleaf varieties is the lace cap hydrangea with blossoms with a flat disk, and a round cap of smaller flowers in its centre. These flowers are surrounded by a fringe of showier, larger flowers. Mopheads have round flower heads while the lane heads have distinctly flattened ones. They are usually 10 to 15 cm long and 7.5 to 15 cm wide. However, in a few cases, they can grow even bigger. They are perfect for a nice, fabulous display in a large container that you can place on your patio.

2. Hydrangea arborescens

These plants are also known as wild hydrangeas. They are hardy plants and can easily tolerate extreme climates. Due to their size, they are often planted as hedges. The leaves of these hydrangea flowers are thin, floppy, and heart-shapedThey have a coarse texture and a matte surface as compared to the relatively smooth leaves of the mopheads. Their leaf stems are long as well and hold the leaves away from the stems. It is a truly magnificent plant species with round blossoms that are up to 15 cm in diameter. They bloom from midsummer to autumn and are breathtakingly beautiful. They are everyone’s favourite for flower arrangements. 

3. Hydrangea paniculata

We all have seen large, cone-shaped blooms that start out as white flowers and then turn into pink ones. These are panicle hydrangeas. They are hardy plants and can bear extreme hot & cold temperatures. As compared to other hydrangeas, their leaves are small, thin, and roughThey are usually 7.5 to 10 cm wide and 7.5 to 15 cm long. The leaves grow from the stem nodes in groups of three and are in the form of a whorl. They are the only form of hydrangeas that will grow into trees as well, depending on the space and area they get. The white hydrangeas bloom from late summer to early autumn and light up gloomy spots with their beautiful, colourful flowers. 

4. Climbing hydrangeas

Climbing hydrangeas are known for their ability to thrive in conditions where other climbers would struggle to survive. They cling up to fences and walls and can survive in extreme conditions. Their heart-shaped leaves act as the perfect backdrop for their beautiful lacy blooms. They bloom from late spring to early summer.

How does ericaceous soil affect hydrangeas?

Hydrangeas are known for their beautiful blooms in varying colours. We all have seen beautiful hydrangeas blooming everywhere, and alluring us with their stunning blue and pink colour. The million-dollar question is – how do the different types of hydrangeas get their different colours?

Hydrangeas in different colours flourishing in a garden

Just because the hydrangea plant you bought at the nursery has blue flowers doesn’t mean that it will remain blue once you plant it at your home. You will be really excited to learn that different varieties of hydrangeas have different colours based on their growing conditions and soil, especially when it comes to pH.

To change the colour of the hydrangeas, you can make use of ericaceous compost. The acidic soil of the compost will produce blue flowers. Get a pH level test kit and make the changes to your multi-purpose compost as necessary. It will take a couple of weeks to convert the neutral soil to an acidic one, depending on its nature. Remember that the soil returns to its original state naturally after some time so you have to make sure that your flowers are getting this kind of compost regularly.

How to make your DIY compost acidic?

Now that we know what it is, let’s unravel the most important part – how to make your own DIY compost acidic? Well, while there is no single ericaceous recipe as the answer depends on the current pH levels of the individual compost piles, making compost for acidic plants is similar to making normal compost. The only difference is that you don’t add lime. 

Ingredients for ericaceous compost

You will need the following ingredients:

  • Oak leaves/Beech leaves

Oaks leaves or beech leaves are an excellent source of carbon that you need to create the compost. As the leaves decompose, they will acidify the soil type. Naturally, these leaves take a long time to decompose. However, you can speed up the process by chopping them up into smaller sections. Try using moist soil as well. Adding sources of nitrogen such as food scraps, manure, grass clippings, etc. will help too.

  • Pine needles

You can buy pine straw from any gardening shop. Fresh needles are most desirable for composts but they take a long time to decompose into mulch. Therefore, you can get grey and dingy bales of pine straw and use them for composting.

  • Coffee grounds

Coffee grounds are an excellent source of nitrogen and help you lower the pH of the soil. If you are a coffee lover, you will be happy to learn about this new use for the spent grounds!

Some coffee grounds next to blended coffee

  • Peat moss

Peat moss improves soil pH and promotes the healthy growth of ericaceous plants. You can easily buy peat moss from the local gardening store – but it might be a bit expensive. 

Steps to create your ericaceous compost

Here are the steps to create your own:

  1. Start with a compost pile with a 15 to 20 cm layer of organic matter
  2. In order to boost the acidity of the compost, you have to use high-acid matter like pine needles, coffee grounds, oak leaves, prunes, etc. 
  3. Next, you have to measure the surface area of the compost pile you have formed.
  4. You have to sprinkle garden fertiliser, preferably dry, at an average rate of almost 237 ml per sq. ft. Get fertiliser made specifically for acidic plants.
  5. After that, spread a layer of soil – about a centimetre – over the compost so that the decomposition process can begin in earnest. 
  6. You have to alternate layers – soil & compost – and water each layer. You have to do this until the compost pile reaches a height of almost 1.5 m. 

If you are going to make an ericaceous potting mix, you have to follow the given steps:

  1. Start with a base of half-peat moss.
  2. Add 20% perlite, 10% compost, 10% garden soil, & 10% sand
  3. If you don’t want to use peat moss, you can use a substitute such as coir. However, peat will give you the highest level of acidity that you need to create an ericaceous mix.

Some wonderful blue flowers in a garden

Who doesn’t love colourful, shiny flowers that brighten up the day and make your living space beautiful? When it comes to growing hydrangeas, you can change their colour by using the right kind of acid soil. Fascinating, isn’t it? With the help of the details we have mentioned above, you can easily create ericaceous compost that will allow you to change the colour of your hydrangeas according to your liking. Don’t forget to water your plants the right way with your garden hose!

Here’s to your beautiful, enchanting garden!

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