The family Ericaceae to which heather belongs has many genera and species, including Rhododendron. The name 'heather' encompasses four genera. Strictly speaking, the word heather encompasses only the genus Calluna, but it is also used as a general term to cover heaths which are principally made up of two other genera, Erica and Daboecia. Botanically, Calluna differs from Erica and Daboecia by its tailed leaves without a stalk. Andromeda is the other genera and are much less widely grown as garden plants.
The links in the document below will take you to descriptions of garden cultivars of each species, taken from the Handy Guide to Heathers.
The hardiness information uses the zones defined by the USDA (United States Department of Agriculture). Zone maps for Europe and the USA are common on the Internet, here are our versions.
A dwarf plant of the northern hemisphere found in Europe, North America and Japan. The majority of the species grown in gardens emanate from the Japanese population where they are found on well separated mountains, each having distinctive groups of plants. Requiring an acid soil, this species has wiry stems and narrow elliptic leathery leaves. The small pink flowers are usually freely borne in spring and summer. Suitable for USDA hardiness zone 2.
Now considered to be an Erica, and thus should be known as Erica spiculifolia
A monotypic genus of evergreen shrubs which is found from the Arctic Circle to North Africa, following the seaboard of Western Europe and extending as far eastwards as the Ural mountains. It has become naturalised in eastern Canada from seed contained in packing material used by early settlers. |
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Heather is commonplace on the moorlands of northern Europe and plays an important role in the ecology of highland regions but it is also found on the dry lowland heaths of western Europe. Grouse, deer and many smaller mammals, reptiles and insects depend on heather to some degree or another for food and cover. Man, too, has made good use of heather through the ages using it for thatching, ropes, bedding and has even made ale from it! Perhaps the most well known use, today, is heather honey.
The name Calluna derives from the Greek word kallunein which means to cleanse, which probably derives from the use of heather twigs as brooms, or from its medicinal properties for treatment of a number of internal disorders. The word heather is thought to derive from a Scottish word haeddre but many variations can be found dating from the 14th century. Another word from that time is the Norse word lyng meaning light (as in weight) no doubt alluding the practice of cutting heather turf for fuel (which is light when dry, compared to grass turf), yet another use of this versatile plant.
Normally Calluna has slightly fleshy linear leaves 2mm (1/10in) long in opposite and closely overlapping pairs, usually dark green becoming purplish in winter. However the species is very variable, from prostrate, 5 x 45cm (2 x 18in), to erect and spreading 60 x 75cm (24 x 30in) with leaves ranging in colour from dark green to bright green, grey, yellow, orange and red which can be glabrous or hairy. The flowering time varies; in the northern part of the distribution it blooms from June to August, whilst in the southern part of the distribution it blooms from August to November. The white to crimson flowers, held usually in one-sided racemes, are normally single with the corolla in four oblong petals, 3mm (1/8in) long, overlapped by a calyx of similar size and colour. Double and bud-flowering forms also exist and generally flower later.
It is an important garden plant providing colour throughout the year. Often gardens are devoted to the growing of heathers with perhaps dwarf conifers and other ericaceous plants, and provide a haven for many species of butterflies. In general, a well maintained heather garden will last 20 years. All are suitable for hardiness zone 5 but some cultivars are suitable for zone 4.
A genus of two species of low evergreen shrubs, D. cantabrica found in W. Ireland, S.W. France and N.W. Iberia, and D. azorica emanating from the Azores. The hybrid, D. x scotica, is of garden origin.
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This small evergreen shrub, 20cm (8in) high spreading to 40cm (16in), is found in the Azores up to a height of 2000m (7000ft) but is only half hardy. The leaves are lanceolate, 5mm (1/5in) long, 5mm (1/5in) wide, dark green above, silver grey below and more recurved than D. cantabrica. The ruby crimson urceolate flowers are borne above the foliage in early summer. It is distinguished from D. cantabrica by the smaller leaves and the lack of hairs on the corolla. It prefers acid soil conditions. It is only suitable for zone 8 if given some protection.
This hardy evergreen sub-shrub, 40 x 70cm (16 x 28in), has glossy dark green lanceolate leaves, white on the underside, 1.5cm (2/3in) long, 6mm (1/4in) wide and normally lavender urceolate flowers, 1cm (3/8in) long, held in terminal racemes well above the rest of the plant from late June to October, which normally drop when finished.
It is thought this plant genus was named after Dabeoc, the youngest son of a Welsh chieftain who founded a monastery on an island in Lough Derg in Ireland. However, we do know that Linnaeus, the Swedish botanist who formulated our present system of latin plant names, reversed the 'o' and 'e' when naming the genus, an error that has been perpetuated ever since.
This heather tends to have two flushes of flowers, the first in early summer and often another in early autumn which continues until frost occurs. The bell-like flowers range in colour from white through lavender to deep purple. It is a useful plant for ground cover and for intermixing with other dwarf shrubs such as western gorse (Ulex gallii) and is particularly effective when planted in drifts of mixed cultivars.
The plant tends to become straggly if not pruned annually. These plants can tolerate a little shade, are more resistant to drought than most heathers, are fully hardy and are best grown in acid conditions.
Daboecia cantabrica is suitable for hardiness zone 6 with protection but some winter damage can occur if planted in heavy ground or frost pockets.
This hybrid of garden origin between the two species above has the compactness of D. azorica and the hardiness of D. cantabrica. It reaches 20cm (8in) in height, spreading to 45cm (18in). The leaves are glossy dark green, smaller than those of D. cantabrica. It is ideal for ground cover in the smaller garden, flowering profusely between June and November. It is suitable for hardiness zone 6.
A genus of nearly 800 species found in a narrow north-south distribution 30°W to 45°E of the Greenwich meridian ranging from the warm wet conditions of western Europe to the dry hot conditions of southern Africa. About 750 species are confined to south of the Limpopo river in S. Africa. They form evergreen shrubs with narrow folded leaves and flowers with 3 bracts, 4 sepals and a corolla. The European species are widely used as ground cover plants providing colour throughout the year either on their own or in association with other ericaceous plants or dwarf conifers. Frost tender and half hardy species are used as conservatory plants.
It does not occur naturally on the American continent, the vast majority of Asia, nor in Australasia but has naturalised in parts of Australia and New Zealand where it is now viewed as a major weed.
The name Erica derives from the Greek word ereiko meaning to break. It possibly derives from the medieval theory that the plant could dissolve gallstones, alternatively, it may refer to the fact that the stems of some species are easily broken.
The European species which are detailed below are an important group of garden plants providing colour throughout the year. Most European species are fully hardy in the UK but some cannot withstand continental winters (details below). They can be difficult to establish in areas prone to drought.
Erica arboreaA common species of upright evergreen shrub found throughout the Mediterranean basin, the Canary Islands and North and East Africa reaching 6m (20ft) in height and spreading to 1.5m (5ft). It varies in hardiness from frost tender to suitable for hardiness zone 7. The bright green leaves, in whorls of 3 or 4, are needle-like, smooth and grooved beneath. Stems on young shoots have many hairs which are branched. The bell-shaped flowers borne in spring are greyish-white and honey scented. It is not as tolerant of lime as commonly supposed and is best grown in acid soil. Young plants should be shaped in the early years to avoid untidy growth. They can be damaged by heavy snowfalls but will break from the base again. |
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Erica australisAn erect evergreen shrub of rather open habit from western Spain and Portugal, reaching 2m (6ft) in height and spreading to 1m (3ft), which although suitable for zone 8, is prone to damage by wind or snow. The leaves are linear, in whorls of 4, dark green above and channelled beneath. The large showy purplish pink flowers are cylindrical, mid-spring to early summer. It requires acid soil conditions. |
Erica carneaA species of low, spreading, fully hardy, evergreen shrubs from the alpine regions of Europe attaining no more than 20cm (8in) in height but spreading to 55cm (22in). They have linear leaves in whorls of 4 and bear urceolate, generally pink, flowers in late winter to early spring. The flowering times of E. carnea vary markedly, plants in milder climates being as much as two months earlier than those in colder conditions. Generally, they can be expected to show flower for 6-8 weeks. It tolerates lime and a little shade. All exhibit a dwarf carpeting habit and with few exceptions, rarely require pruning. Care must be taken when pruning as E. carnea buds as early as July. It is safer to prune immediately after the flowers have faded. Prune around the edges and very lightly over the top of the plant. It is one of the hardiest of all heaths, suitable for hardiness zone 4. |
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Erica ciliarisA species of loose evergreen shrub from south and south-west England, north-west France, north-west Spain and Portugal. It grows to 35cm (14in) in height and spreads to 50cm (20in), having grey-green or dark green ovate leaves above, white beneath, usually glandular and borne in whorls of 3. It has long racemes of flowers from mid-summer to mid-autumn, usually lilac pink, sharply contracted at the mouth. It prefers moist, acid, sunny positions and is suitable for hardiness zone 7 with protection. |
Erica cinereaAn evergreen compact shrub from western Norway, UK, France, northern Spain and Portugal. It has also naturalised on Nantucket Island, Massachusetts, USA. Reaching 35cm (14in) in height and spreading to 80cm (32in), it usually has leaves which are dark bottle green, linear and strongly revolute. The bell-shaped flowers of white, pink or purple are borne in profusion from early summer to early autumn. It requires an acid soil, an open sunny position and is suitable for hardiness zone 7 provided some protection is given against dessicating winds. |
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The original hybrid between Erica carnea and Erica erigena was found in a nursery in Darley Dale, Derbyshire, England at the turn of the century. This bushy fully hardy evergreen shrub attains 70cm (28in) in height and spreads to 80cm (32in). It is one of the easiest heathers to grow, being suitable for all soils and is particularly good at smothering weeds. Most of these hybrids are sterile, have a long flowering period in spring and exhibit coloured young foliage. It is hardy to zone 7.
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Erica erigenaA species of upright evergreen shrub having rather brittle stems reaching 2.5m (8ft) in height, spreading to 1m (3ft) which has dark green linear leaves and flowers during the winter and spring with deep lilac, honey scented, urceolate bells. It is native to western Ireland, north-west Spain and Portugal. Suitable for hardiness zone 7, it can be grown with protection in zone 4, where some damage can occur but the plant usually recovers well from the base. It can be grown in most soils and is very suitable for low hedging and as an 'architectural' feature where heavy snowfall is not expected. |
A hybrid between Erica manipuliflora and Erica vagans. These lime-tolerant hybrids have the vigour of E. manipuliflora and the compactness and early flowering of E. vagans. Some outstanding cultivars been produced by deliberate breeding but some are of garden origin. They are similar in height to Erica manipuliflora but are slightly more hardy, suitable for zone 6. The species is named after Prof. John Griffiths, the first person to make the deliberate cross.
Deliberate hybrids between Erica carnea and Erica spiculifolia which have a very long flowering period with tiny flowers similar to E. spiculifolia. Most exhibit brightly coloured new growth in spring. The species is named after Kurt Kramer who was the first, and to date the only, person to make the cross. There are a number of clones which to date have not been named. They require an acid soil and are suitable for zones 5-9.
Erica lusitanicaAn elegant erect evergreen shrub from south-west France, north and western Spain and Portugal. It attains 3m (10ft) in height, spreading to 1m (3ft) with fine linear glabrous leaves. It has the longest flowering period of any tree heath, with pink buds opening to white tubular to campanulate flowers in winter and spring. It will grow in most soils and is suitable for hardiness zone 8. |
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Erica mackayanaA spreading evergreen shrub reaching 1m (3ft) in height, spreading to 75cm (30in) from northern Spain. It also occurs in western Ireland where it rarely grows taller than 30cm (12in). It has lanceolate, dark green leaves with a white under-surface. The urceolate bright pink flowers, contracted at the mouth, are borne in summer and early autumn. White and double-flowered forms exist. The Irish population is hardy to zone 7 with protection but the taller, more vigorous population from Spain varies from zone 8 to zone 7. All forms require damp acid soil conditions, and provide neat ground cover but are very suspect in dry conditions. E. mackayana produces new shoots from the roots which can be detached to form new plants. |
Erica manipulifloraAn eastern Mediterranean species of evergreen, lime-tolerant shrub attaining a height of 1m (3ft) and spreading to 1.1m (3ft). It has rose-pink, campanulate flowers in late summer and autumn. There is considerable variation in the species, some plants having brown stems and linear leaves to 7mm (in) and others having narrow interrupted inflorescences, very short leaves and whitish stems. It is a very useful species as it is lime-tolerant and happily grows on magnesium-deficient soils unlike Erica vagans. Suitable for hardiness zone 8. |
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Erica multifloraSomewhat similar to Erica vagans with close racemes of flowers of similar colour range although white is very uncommon. The flowers are held on very long pedicels which are normally much deeper in colour than the corolla. Unlike Erica vagans, the whole raceme opens together and can provide a spectacular display. It is lime tolerant but is not really hardy. It usually has an erect habit and can make large shrubs 200cm high 100cm spread. Suitable for hardiness zone 9. |
Deliberate hybrids between Erica arborea and Erica carnea which form small compact arborea-like tree heaths which have inherited the extreme hardiness of E. carnea. Most exhibit brightly coloured new growth in spring. Lime tolerant and suitable for zones 5-9.
Erica scopariaA species of evergreen shrub sub-divided into three subspecies. Subspecies azorica, native to the Azores is surprisingly suitable for zone 6. It has small chesnut flowers with a smaller calyx and corolla than the other subspecies. With an attractive habit, it grows to 1m (3ft), spreading to 75cm (30in); the half-hardy subspecies platycodon from the Canary Islands has large leaves 9mm (3/8in) long, and reaches tree-like proportions of 10m (30ft) in height and 6m (20ft) across. It is the least hardy of the subspecies, only suitable for zones 6-9. Subspecies scoparia is the most widely distributed, native to central and southern France and the Iberian peninsula, Corsica and Sardinia. It makes a rather untidy bush reaching 2m (6ft). It varies in hardiness, being generally suitable for zone 7, although some of the more dwarf cultivars are suitable for zone 6. They have tiny brownish-green flowers in late spring and early summer which smother most of the preceding year's growth and produce clouds of pollen. subspecies maderincola is only found on the islands of Madeira and nearby Porto Santo. It closely resembles ssp. platycodon but has a laxer habit, longer leaves even more spaced and spreading when mature, a shorter calyx and corolla with the stigma more exserted. Suitable only for zones 6-9. All subspecies require acid soil conditions. |
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A naturally occurring hybrid between E. mackaiana and E. tetralix requiring moist, acid soil conditions. It is native to Connemara and Donegal in Ireland. It is apparently absent from north-west Spain, the only other area where the two parents co-exist. The habit and cultural conditions are similar to the Irish form of Erica mackaiana. All of these sterile hybrids exhibit brightly coloured spring growth and are suitable for hardiness zone 7.
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Erica terminalisThis lime-tolerant species of erect evergreen shrub is native to southern Spain, Corsica, Sardinia and southern Italy. It grows to 1.5m (5ft) in height, spreading to 1m (3ft), and bears terminal umbels of lilac-pink, urceolate flowers mid-summer to early autumn. The faded bells provide an attractive russet hue all winter. It is surprisingly hardy and is suitable for zone 5. |
Erica tetralixA widespread species of evergreen shrub throughout western Europe from the Artic Circle to southern Spain. It grows to 30cm (12in), spreading to 50cm (20in) with narrow, usually glandular, grey-green leaves, white beneath, arranged in whorls of four to form a cross. The pale pink, urceolate flowers, contracted at the mouth, are held in terminal umbels from mid-summer to mid-autumn. Although usually found in boggy areas in the wild, it is tolerant of drier conditions when brought into the garden. It requires acid, preferably moist, soil and is suitable for zone 4. |
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Erica umbellataA very useful and colourful species of evergreen shrub of neat compact habit having grey-green linear leaves in whorls of three, and globose mauve flowers with conspicuous dark brown exserted anthers. It is native to north-west Spain and Portugal. It requires well-drained soil that need not be acid, where it will attain a height of 45cm (18in) and a spread of 55cm (22in). Suitable for zone 8. |
Erica vagansA species of evergreen shrub native to the Lizard peninsula in Cornwall, England, Brittany and south west France and northern Spain. They grow to 50cm (20in) and spread to 80cm (32in) with linear, dark green leaves and small, campanulate, pink, mauve or white flowers held in cylindrical racemes from mid-summer to mid-autumn. It can be sucessfully grown on any soil rich in magnesium and responds well to hard pruning. It is suitable for zone 5 provided the dead flowers, which are an attractive russet in winter, are kept on the plant. |
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A hybrid between E. arborea and E. lusitanica which varies in hardiness from zone 7 to zone 8 depending on the cultivar. It can be grown in most alkaline soils. All are of garden origin.
A naturally occurring sterile hybrid between E. ciliaris and E. tetralix first found in Cornwall, England in 1831. The form and habit varies considerably but generally they have a long flowering period and brightly coloured tips to the foliage in spring. They require acid soil conditions and are suitable for zone 7.
A naturally occurring sterile hybrid between E. vagans and E. tetralix first found on the Lizard peninsula, Cornwall, England in 1860 and known nowhere else. It will grow on most alkaline soils. All exhibit, some more than others, bright yellow tips to the spring growth. The flowers closely resemble those of E. vagans. Suitable for hardiness zone 5.
© The Heather Society, 29 September 2008