Can You Use Ericaceous Compost For Roses? 🌹

Reading Time: 8 minutes 🍃

Ericaceous compost, or acid-rich compost, can be beneficial to many garden plants, flowers, and vegetables. Roses are a special favorite of many gardeners, and you may be wondering if ericaceous soil can benefit your rose garden. Can you use ericaceous compost for roses?

Roses can benefit from ericaceous compost when the soil they’re planted in is naturally alkaline. Ericaceous compost can help decrease the pH levels of acid-weak soils and help roses to grow to their fullest potential. Ericaceous compost can harm a rose, however, if the soil is already naturally acidic.

Keep reading to learn more about the acidity needs of roses, how and where to use ericaceous compost, and the best composting habits for your rose garden.

Table of Contents

Do Roses Like Ericaceous Compost?

Roses do best in slightly acidic soil, with a pH level of 6.0 to 6.5. The higher the pH level numerically, the more basic or non-acidic a material is. The lower the number, the more acidic the material. For example, battery acid ranks a “0” on the pH scale, as it is very acidic to the point of being dangerous to human skin, whereas liquid drain cleaner ranks a “14” and is also chemically very powerful yet alkaline.

Ericaceous compost increases the acidity of the soil and can be beneficial if the soil you’re seeking to plant your roses in is alkaline. Calcium-rich soils tend to be alkaline, and any soil at or above an 8.0 pH level is going to be alkaline in nature. Additionally, soils in rocky or arid terrains are more likely to be alkaline.

Alkaline soil is great for some plants, but for those that thrive in mildly acidic soils, like roses, adding ericaceous compost to acid-poor soil will help your plants grow to their full potential and look their most beautiful.

You Can Test Your Soil’s pH Level

So, how do you know if the soil in your garden is acidic or alkaline? One of the simplest ways to do this is with a home pH level testing kit, available in most home and garden stores. Some basic soil moisture-monitoring devices can test for pH levels, too.

Another way to test your soil, albeit a less precise way, is to get a general sense of the acidity or alkalinity of your soil with basic kitchen ingredients. Secure two small samples of your garden’s soil. About one trowel-full per sample should be sufficient. Keep each sample in a separate, disposable container, such as a small paper bowl.

To one soil sample, add about ½ cup of distilled water, and mix into the soil thoroughly. Next, add ½ cup of white vinegar. If you notice a foaming or bubbling action within the soil, your soil is on the alkaline side.

Now, turn to your second sample. Add ½ cup of distilled water to this sample, too, and mix it in well. Then, add ½ cup of baking soda to the dampened soil. If you notice foaming or bubbling in this particular sample, your soil is on the acidic side.

This basic test won’t give you an exact pH level but can help you determine roughly which side of the pH spectrum your soil is on. If your soil tests out as more alkaline, ericaceous compost can definitely help increase the acidity of your soil and make it a better environment for roses.

Which Soils are Acidic vs. Alkaline?

While it’s best to test your property’s spoil for pH levels, there are some general rules for assuming the acidity vs. alkalinity of your soil.

Broadly speaking, soils that are drier, high in clay content, and retain moisture poorly are going to be alkaline. This is often true of dry or mountainous soils in regions where rainfall can be scarce.

Alkaline soils tend to contain higher levels of sodium, calcium, and magnesium, and you might notice a few plants apart from pine trees and scrubby shrubs growing naturally and successfully in alkaline soil.

Acidic soil tends to be more common in wooded or traditionally wooded areas and in regions with heavier rainfall. The quantity of plant matter that breaks down and biodegrades in these biospheres tends to increase the acidity of the soil. As a result, acidic soils also tend to contain high levels of nitrogen, which is favored by many plant species and provides valuable nutrition through the plant’s root system.

So, while we tend to associate “acid” in our everyday vocabulary with something dangerous or damaging, mildly acidic soils can benefit plant life and provide a powerful dose of nutrients to help flowers and vegetables grow well.

Ericaceous Compost Can Improve Alkaline Soil

Acidity in the soil helps many plants to absorb the maximum amount of beneficial nutrients from that soil, through their roots. Alkaline soil can be a bit harder to benefit from, but some plants are designed specially to thrive in calcium-rich, non-acidic environments.

Not roses, though. Roses require slightly acidic soil. In fact, many plants do better in lightly acidic or neutral rather than alkaline environments. This is especially true of decorative flowering plants and shrubs.

Naturally, neutral-to-acidic soils tend to have denser levels of nutrients, as well, meaning that there’s more food on the earth for plants to absorb and benefit from. If you’re trying to grow roses in alkaline soil, ericaceous compost can help increase local acidity and make growing and flourishing easier for roses.

You Can Make Your Own Ericaceous Compost

One of the least expensive and most fun ways to help improve alkaline soil for growing roses is to make your own ericaceous compost at home. Simply set aside and compost materials and organic scraps that will help improve acidity, such as

Fallen tree leaves
Pine needles
Coffee grounds or used tea bags (minus any plastic)

Orange peels, lemon rinds, or grapefruit rinds (anything citrus, basically)
Bark or sawdust

These materials will be best for creating a truly acidic compost that can boost the acidity of alkaline soil. Your roses will love it, and so will many other plants and flowers in your garden.

You can also test the acidity of your compost with pH strips as it matures to ensure it’s acidic enough to meet the needs of your roses. Once your compost has properly matured, simply scoop it out by the shovel-full and mix it thoroughly with the topsoil of your garden.

Ericaceous Composts Can Sometimes Harm Roses

While adding acidity to alkaline soil will benefit roses, if the soil on your property is already neutral-to-slightly-acidic, adding ericaceous compost to your garden can harm your roses.

Roses are rather finicky. They need rather precise levels of acidity in the soil to really do their best, and if the soil you’re growing them in is already 6.0 – 7.0 in pH, adding ericaceous compost can over-saturate the earth with acid, and make it harder for your roses to grow.

Soil that is too acidic can make it difficult for roses to absorb nitrogen, potassium, and phosphorus. As a result, roses can look stunted, bloom less frequently or beautifully, or even struggle to survive in soil that is too acidic. So, unless your soil is alkaline, there’s really no reason to add ericaceous compost.

General-Use Composts Are Often Best for Roses

If your soil is already adequate for growing roses, there’s no need to add more acid to the soil. That doesn’t mean that your roses can’t benefit from compost, however, and there are wide varieties of compost that can help boost your roses’ growth and health without lowering your soil’s pH levels further.

A loam-based compost will be rich in nutrients and yet have a neutral pH level, making it perfect for roses and other sensitive decorative flowers. Cow manure-rich composts and fertilizers can also be excellent for promoting rose growth, as these are rich in nutrients and help the soil to maintain moisture better.

Most commercial potting soils are also carefully formulated with balanced amounts of nutrients, organic materials, and moisture-retaining elements and would be suitable for growing roses. Potting soils can be used to bolster the nutrients of natural soil and can be used in your garden along with other natural fertilizers to help roses grow to their full potential and bloom longer.

Why Are Roses So Finicky?

My goodness, roses are demanding! Everything must be just so, the soil must be at a very precise pH level, and even with the best care, roses can struggle to grow. Why is this?

Roses have been bred over the centuries for a few key qualities, namely the beauty and large size of their blooms and their bloom color. Roses tend to be delicate, however, and are not very good at fighting off disease. While they have been bred very successfully for color, this beauty has come at the expense of disease resilience and hardiness.

Roses do love sunlight, at least six hours of sun per day, so make sure that you’re not trying to grow them in the shade. They also appreciate a substantial amount of water, twice a week, unless you’re in a naturally rainy climate, paired with soil that naturally drains well to avoid drowning the roots.

And, as explained, they love nutrients and fertilizer, but not too many nutrients and not too much fertilizer. This is a reflection of their very specific pH requirements and the years of selective breeding, which have left them gorgeous, but a bit delicate and rather fussy.

Which Plants Love Ericaceous Compost?

While roses do well in neutral to mildly acidic soils, and while many gardens won’t need ericaceous composts, some plant varieties do very well in higher-acidity soils.

If your garden is already perfect for growing roses (6.0 – 6.5 pH levels and lots of sunlight), you can still find some flowers and shrubs that would love a more acid-rich environment. Plant species that thrive in more acidic soils include

Heathers
Blueberries

Rhododendrons
Hydrangeas
Azaleas

Ferns
Camellias
Pieris

So, if your rose garden is already looking beautiful and you need a home for all of that ericaceous compost that you went ahead and made before reading the full article, the plant species above would be thrilled to be planted with it! Feel free to use this compost at a distance from your roses or in raised flower beds in which other species are growing.

This video goes into more depth about what it takes to grow the best roses.

Lime Can Raise Alkaline Levels

If your soil levels are a bit too acidic for roses, there are some ways to neutralize that acidity and raise the pH levels to be suitable for rose growth.

For example, if your soil pH level is 5.5, this makes it ideal for azaleas and conifers but a bit too acidic for roses to flourish or be healthy. To raise the pH level of your soil in this case, adding ground limestone to your soil can help immensely.

The finer the limestone, the quicker it will increase the alkalinity of your soil. Be careful with lime, as it can increase the pH level of soil very quickly. Use a modest amount of fine-ground lime, work it into the soil, and water immediately to help begin to raise the pH level of your garden.

Lime can be found at most home and garden stores. Use pH testing strips to determine if the lime has been sufficient to raise the pH level to a healthy 6.0 – 6.5.

Conclusion

Roses prefer soil with a pH level of 6.0 to 6.5 and therefore do not require ericaceous compost unless they are being grown in soil with an 8.0 or higher pH level.

If your garden’s soil is more alkaline, you can increase the acidity with a natural ericaceous compost made from coffee grounds, citrus rinds, leaves, bark, and pine needles.

In normal, mildly acidic garden soil, roses do best with a neutral-pH compost or with natural cow manure. If the soil you are growing roses in is too acidic, the pH level can be raised by adding ground limestone to your soil and then watering.

Sources

Was this article helpful?

YesNo