Cultivation notes

Heathers (Calluna), heaths (Erica) and Irish heath (Daboecia) thrive in an open, sunny position, but will tolerate light shade, such as under high-canopied deciduous trees. Many need lime-free soil (acidic) that is rich in organic matter. Some tolerate neutral to alkaline soil.

Heathers for acidic soil

These flower from late summer to autumn and include all Calluna and Daboecia cantabrica. They need neutral to acidic growing conditions, which means a pH of 6.5 or less, ideally 5.5. These heathers need a light sandy soil, enriched with organic matter.

Heathers tolerating a neutral to alkaline soil

Winter and spring flowering Erica carnea, E. × darleyensis, and the summer flowering E. vagans will tolerate a slightly heavier soil (than the acid-loving heathers). They will grow in an acid soil or neutral to alkaline soil (pH reading of 7.0 or higher) as long as there is plenty of well-rotted organic matter.

Use homemade leaf mould, well-composted pine needles or composted pine bark. Use when planting heathers and as a mulch to keep soil acidity up and improve soil structure.

For the more alkaline-tolerant ericas, incorporate well-rotted garden compost or farmyard manure at planting.

Feeding

Heathers in open ground do not need feeding if conditions are acidic. If soil becomes too alkaline, yellowing of the foliage may occur. In this case, feed with an ericaceous fertiliser in late March or early April.

Newly planted specimens in containers will have enough feed from the compost for a couple of months. Subsequently, apply a fertiliser produced specially for ericaceous plants during the growing season as per the packet instructions.

Pruning and training

Limit pruning of Erica, Calluna and Daboecia to trimming faded flowering stems back to bases straight after flowering (pruning group 10). Heathers do not regenerate well from old wood, so once they have become woody and leggy, replacement is the best option. Alternatively, consider propagating the plant by ‘dropping’ (see propagation section).

Tree heathers

These make attractive summer flowering shrubs or informal hedges and these species, along with their cultivars reach heights of between 1.2m (4ft) to 4m (13ft).

They respond well to being pruned and like other heathers, their flowers are loved by bees. These include Erica arborea (acid soil), E. lusitanica (acid or alkaline soil), E. × veitchii (tolerates alkaline soil) and E. australis (acid soil).

For the first two or three years after planting, prune Erica arborea back by two-thirds. After this, little pruning is necessary (pruning group 10). Renovation of  E. arborea is very successful and it regenerates well, when cut back into old wood.

E. australis and E. lusitanica need minimal pruning and are also in pruning group 10.

Propagation

Cuttings

Take semi–ripe cuttings of Daboecia and Erica in July or August and of Calluna from August to September. Select and cut 10cm (4in) non-flowering sideshoots. Trim this material to 5cm (2in). Keep the cuttings covered with a propagator lid or plastic and keep in a shaded position for up to 8-12 weeks.

Layering

An easier method of propagating heathers is by layering in spring.

Dropping

Should you have a heather that has woody stems and all the growth towards the top of the plant, it is possible to start all over again by producing individual rooted cuttings from the old plant. Spring is the time to start this project.

1. Dig the plant up and replant it in a hole large enough to bury two thirds of the plant.
2. Settle the soil back round the roots.
3. Make a mixture of half grit and half coir and work it around the stems of the heather, right up to soil level. The shoots will be visible.
4. Firm the soil carefully.
5. Water the heather in dry weather and in autumn lift the whole plant.
6. Sever the rooted shoots from the parent plant and pot up the rooted cuttings singly or plant directly into their new permanent positions.
7. Discard the old plant..

Cultivar Selection

Winter-Spring (acid, neutral or alkaline soil)

Erica carnea ‘Myretoun Ruby’ AGM: Dark green foliage. 15cm (6in) in height and 45cm (18in) wide. Flowers of deep rose-pink to magenta
Erica carnea ‘Springwood White’ AGM: Mid to bright-green foliage, to 20cm (8in) in height and 45cm (18in) wide. Flowers white
Erica carnea f. aureifolia 'Foxhollow' AGM: Yellow-green young foliage, becoming reddish-orange in winter. 25cm (10in) by 45cm (18in). Flowers pale-pink to pale-purple
Erica × darleyensis ‘Ghost Hills’ AGM: Bright green foliage, tipped cream in spring. 50cm (20in) in height x 1m (3½ft) wide. Flowers purple, darker near the tip, in late winter and early spring
Erica × darleyensis f. aureifolia ‘Tweety’: Golden foliage, turning to orange in winter. 30cm (12in) x 45cm (18in). Magenta flowers.

Erica lusitanica f. aureifolia ‘George Hunt': Golden-yellow foliage. Height 1.5m (5ft). Scented, white flowers opening from pink buds from late winter to mid spring. Neutral to acid soil
Erica arbora var. alpina:  Medium-sized evergreen shrub to 2m (6½ft) in height, with bright green foliage. Small, fragrant white flowers. Neutral to acid soil

Summer-Autumn (acid soil)

Calluna vulgaris 'Dark Beauty' (PBR) AGM: Dark green foliage. 25cm (10in) in height. Spikes of dark cerise flowers deepening to ruby-red
Calluna vulgaris 'Firefly’ AGM: Red-brown foliage, becoming bright orange red in winter. 50cm (20in) x 50cm (20in). Flowers purplish-pink
Erica cinerea ‘Pink Ice’ AGM: Dark green foliage. 20cm (8in)  x 40cm (18in). Flowers clear light rose-pink (tolerates neutral to alkaline soil)
Calluna vulgaris ‘Robert Chapman’ AGM: Golden-yellow foliage which turns coppery-red in winter and spring. Height 25cm (10in). Light purple flowers
Calluna vulgaris ‘Spring Cream’ AGM: Dark green foliage tipped with cream in the early summer. Height 30cm (1ft). Flowers single and white

Autumn to winter (acid soil)

Calluna vulgaris ‘Garden Girls’ bud bloomers series are a range of callunas suitable for containers as well as borders. The buds remain closed, but give plenty of colour for several months

Calluna vulgaris 'Alicia' (PBR) (Garden Girls Series) AGM: is a "bud-blooming" heather to 25cm (10in), with very long-lasting white flowers in late summer and autumn

Planting combinations with heathers

The best planting companions may include pines (all sizes to choose from), white stemmed birches, mountain ash species and cultivars (Sorbus), Cornus, acid-loving Gaultheria mucronata and Vaccinium. Grasses can produce attractive foliage contrasts.

Add spring-flowering bulbs such as snowdrops, Iris histrioides and Iris reticulata cultivars.

White flowered heather such as Erica carnea f. alba ‘Whitehall’ with cream edged holly (Ilex ‘Argentea Marginata'), for example, along with lemon and white blooming Narcissus cyclamineus ‘Jenny’ is an example of a planting combination and could also be used in containers. Calluna vulgaris ‘Garden Girls’ bud bloomers series are also suitable for containers.

Problems

Heathers can suffer from Phytophthora root rot, especially in warmer climates.

Rabbits and deer grazing in rural areas.

Where to see heathers

RHS Wisley, Woking, Surrey GU23 6QB National Collection of Erica:

Nymans Garden, Handcross, near Haywards Heath, West Sussex, RH17 6EB National Collection of Erica and Calluna

The Lakeland Horticultural Society, Holehird Gardens, Patterdale Road, Windermere, LA23 1NP National Collection of Daboecia

RHS Garden Harlow Carr Crag Lane Harrogate North Yorkshire HG3 1QB

Further reading

Gardening with Hardy Heathers by David Small & Ella May T Wulff  (Timber Press, 2008, ISBN: 9780881927825)

This books is made available through the RHS Library.