Horticulture Definitions of Ericaceous

The word Ericaceous is often found in gardening books and has four related definitions within horticulture:

1. Ericaceae: the heather family
2. Calcifuges: all plants which dislike alkaline (chalky) soil including heathers, rhododendron, and camellia. These plants are also described as ericaceous, as the prototypical calcifuge is the genus Erica (heaths)
3. Ericaceous bed: a bed with acidic soil typically having a pH between 4.5 and 6 used for growing Calcifuges
4. Ericaceous compost: a commercial formulation of growing medium designed specifically for ericaceous plants in containers

Ericaceae, the Heather Family

Ericaceous trees and shrubs are those that belong to the plant family Ericaceae. A key characteristic of these shrubs is the fact that they need infertile or acidic soil. The word ericaceous is also sometimes used to describe any plant that likes acid soil, regardless of family.

Examples of ericaceous trees and shrubs include:

• Azaleas
• Bearberries
• Blueberries
• Cranberries
• Heather & heaths
• Pieris
• Rhododendrons
• Strawberry tree
• Whortleberry

Calcifuges 

A calcifuge is a plant that does not tolerate alkaline (basic) soil. The word is derived from the Latin 'to flee from chalk'. It applies to any plant incapable of thriving in calcareous soil, or soil that contains a great deal of calcium carbonate from underlying chalk or limestone rock. These plants are also described as lime-haters or ericaceous.

Ericaceous Bed

Some of the very finest fruits come from acid-loving berries. All these berries grow naturally in acidic soils somewhere between pH 4.0 and 5.0. Neutral soil has a pH of exactly 7.0, with acidic soils sitting below this level and alkaline soils above it. The particularly low range of ideal pH for these acid-lovers means that few of us have soil that's a perfect match. The solution is to grow them in pots of acidic potting soil (also called ericaceous potting soil) or in a specially prepared ericaceous bed.

The best way to make an ericaceous bed is to prepare a tailor-made growing environment within a raised bed. This will save you from digging out your existing soil. The bulk of the planting medium should be ericaceous compost. To this, you can add garden-made compost, well-rotted manure, composted bark, sawdust or wood shavings, leaf mold, or pine needles. The object is simply to create an acidic environment that's rich in organic matter and that's springy and free-draining, just like the woodland floor and heathland environments where these plants grow in the wild.

Ericaceous Compost

In simple terms, ericaceous compost is compost suitable for growing acid-loving plants. While there’s no "one size fits all’ ericaceous compost recipe, as it depends on the current pH of each pile, making compost for acid-loving plants is much like making regular compost. No lime is added, though. 

Begin your compost pile with a 6- to 8-inch layer of organic matter. To boost the acid content of your compost, use high-acid organic matter such as oak leaves, pine needles, or coffee grounds. Although compost eventually reverts to a neutral pH, pine needles help acidify the soil until they decompose.

In addition to the plants listed above, these will also benefit from an ericaceous bed and compost.

• Camellia
• Japanese maple
• Gardenia
• Hydrangea
• Viburnum
• Magnolia
• Bleeding Heart
• Holly
• Lupine
• Juniper 
• Pachysandra
• Fern