Do Box Plants (Buxus sempervirens) Need Ericaceous Compost?

Buxus sempervirens

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Box plants are an interesting shrub favored by gardeners as a mid-level shrub or a small tree to fill space at an intermediary level between short plants and tall trees and cultivated and manicured as a hedge. Do box plants need ericaceous compost to grow well, or do they prefer less acidic soil?

Ericaceous compost is not generally recommended for growing box plants. The commonly stated pH range for growing box plants or Buxux sempervirens is between 5.5 and 7.2. However, box plants grow better when the pH is above 6.0 and grow best in slightly alkaline soil of 7.2 pH.

We will explore box plants’ soil preferences, ericaceous compost‘s role, and whether it is necessary or beneficial to use this type of compost with box plants. Our goal is to offer a clearer understanding of how to care for your box plants and ensure their healthy growth.

Is Ericaceous Compost Good For Box Plants?

Box plants, also known as Buxus sempervirens, are popular for gardeners and landscapers. With their evergreen foliage and ability to be shaped into a variety of forms, they make excellent hedges, topiaries, and border plants. 

However, when it comes to caring for box plants, there are several questions that arise, including whether they require ericaceous compost.

Ericaceous compost is a specialized type of soil amendment that is typically recommended for plants that prefer acidic soil. Is this growing environment suitable for planting box plants?

To find out whether ericaceous compost is needed to grow box plants, we need to get some background on the ideal growing conditions for these plants.

Do Box Plants Prefer Acidic Soil?

Box plants are natives from the regions of south and western Europe, northwest Africa, the northern Mediterranean, southern England, and southwest Asia.

This wide distribution means that the plant has acclimatized to a wide range of growing conditions, but certain conditions will produce better results when gardening with these evergreen shrubs.

The box plants growing in the Mediterranean region have been found to grow well in fairly alkaline soils with a pH range of 7.0 to 8.5. Box plants from most other regions are typically planted in slightly alkaline soil to neutral pH soil.

However, box plants have also been grown in soils with a pH of 5.5, which is substantially lower than the pH of soils found in their natural habitats.

This indicates that box plants have a wide soil pH tolerance, but all plants, even those with a wide tolerance, will have a soil pH sweet spot where they will grow the best.

Consequently, while box plants are known for their tolerance to a range of soil conditions, they prefer slightly acidic to neutral to slightly alkaline soil. The 6.5 to 7.2 pH range is generally considered the best range for growing box plants. This is partly due to their ability to take up nutrients more efficiently in an alkaline environment. 

Acidic soil, on the other hand, can make it more difficult for box plants to absorb certain nutrients, such as calcium and magnesium, which can lead to yellowing leaves and stunted growth.

Even though box plants can tolerate slightly acidic soil, it is generally not recommended to plant them in highly acidic soil with a pH below 6.0. 

This can result in a range of problems, including poor nutrient uptake, reduced growth, and increased susceptibility to pests and diseases.

When To Use Ericaceous Compost With Box Plants

Considering that box plants prefer slightly acidic to slightly alkaline, does this mean that ericaceous compost has no value when planting box plants?

In most cases, this is true, as most standard garden soil pH values will generally be suitable for growing box plants.

The only circumstance where ericaceous compost will benefit box plants is when your region’s soil is strongly alkaline.

While box plants can tolerate alkaline soils, if the soil is strongly alkaline, it will have the same effect as a strongly acidic soil. The box plant will be unable to absorb nutrients from the soil, and the alkalinity may lock up some of the minerals and nutrients in the soil, making them unavailable to the plant.

Strongly alkaline soils are often found in drier, low-rainfall regions, particularly where the dominant rock formations are limestone.

Using Ericaceous Compost On Alkaline Soils

Ericaceous compost can be added to strongly alkaline soils to lower the soil pH to the 6.5 to 7.2 pH range to produce optimal growing conditions for your box plants.

The best way to amend the soil with ericaceous compost is to take a pH reading of your garden soil to establish the starting point pH level.

Mix 50% of your garden soil with 20% ericaceous compost, 20% perlite, and 10% standard compost. Moisten this mixture and test the pH level to establish the new level. If the mixture is still too alkaline, add another handful or two of ericaceous compost and retest the pH of the mixture.

Repeat this process until the desired pH level is reached. This mixture can then be used when planting your box plants in strongly alkaline soils.

The mixture will slowly revert to the pH of the surrounding soil over time, so it is important to monitor the soil pH every 6 to 8 weeks to ensure the pH is still within the optimal range for box plants. As the pH rises, you can top-dress the soil with ericaceous compost to lower the pH.

Alternatives To Ericaceous Compost For Box Plants

If your soil is pretty standard, with a pH of between 6.0 and 7.0, your should be able to use standard compost or compost containing a little lime to raise the pH to almost neutral or slightly alkaline.

This will provide the best alternative to ericaceous compost when your soil is already on the slightly acidic side.

Check out: Using Ericaceous Compost for Bedding Plants


While box plants prefer slightly alkaline soil, there may be situations where using ericaceous compost can be beneficial. However, the specific effects of ericaceous compost on soil can result in acidity levels that are not conducive to healthy box plants. Standard compost or compost amended with some lime may be more effective, depending on your local soil conditions.

Regardless of whether you use ericaceous compost or an alternative, it is important to monitor the health of your box plants and make adjustments to your soil amendments as needed. By creating a healthy growing environment and providing proper care, you can enjoy the beauty and versatility of box plants in your landscape or garden.


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