Heathers can be quite a confusing group for consumers and gardeners. Most people believe they are acid lovers and tricky to grow, so even otherwise well-trained garden centre staff end up offering incorrect advice about them. But the need for ericaceous soil is a simplistic view because winter- and spring-flowering heathers are actually not that fussy about pH and can even tolerate slightly chalky soil.
A little research and a thorough check on what type of heather is in front of you should be enough to reassure the grower. Heathers are worth growing for their lovely colourful flowers and often colourful foliage too. They provide a highly valuable evergreen presence once herbaceous perennials have died down. They are also being used more and more in container planting, in both the summer and winter.
Heathers are all evergreen, woody-stemmed shrubs, varying in height from tree heaths that can grow up to 6m to dwarf prostrate plants that form good ground cover. They range in hardiness from fully hardy to only frost tender, needing a minimum of 5-7°C. There are three genera — Calluna, Daboecia and Erica. The largest genus is Erica, with species that flower in every season.
The heathers that flower in winter or spring are varieties of E. carnea,
E. × darleyensis and E. erigena. These are arguably the easiest to grow because they are fully hardy and will grow on acid or slightly alkaline (chalky) soils. They generally flower all winter into early spring.
The summer-flowering heathers include the two species of Daboecia; C. vulgaris, the only species in its genus to have spawned a huge number of cultivars; and some species of Erica, including cinerea, tetralix, × williamsii, ciliaris, × watsonii, × stuartii and mackayana.
C. vulgaris flowers not just in midsummer but into late autumn. This species and the summer-flowering Erica require an acid soil and a lighter soil structure that can be easily penetrated by the plants’ fine roots.
All heathers are best grown in acid soils so if using them for container displays they should be planted in ericaceous compost. However, certain varieties can tolerate slightly alkaline soil so this may help those who covet a heather garden but have slightly chalky conditions.
Heathers have fine roots so they need a nice friable, moist but well-drained soil, so lighten up heavy soils or add humus to lighter soils. Ideally, plant them in a nice sunny position, though some cope with light shade, and water in well during summer if planting in spring.
To plant heathers en masse, use eight-to-nine 9cm plants or four-to-six one-litre plants per square metre. Give plants a light trim to the base of the flowering spike after flowering. Do not cut them back hard because this will leave bare woody areas.
Stephen Morrison, manager, The Speyside Centre, Inverness-shire
"With so many advantages for the gardener, it is no surprise to find that heathers are more popular than ever. Providing colour all year round with foliage and flower, heathers are evergreen, hardy and will thrive for many years. They are inexpensive and relatively easy to grow.
"Once established, heathers will provide a weed-free garden that requires minimum maintenance. Relatively free from pests and diseases also, it is small wonder that the plants are widely used in landscape projects, large and small.
"Use ericaceous compost if planting heathers in pots. Ensure that plants do not dry out and use feed suited to rhododendrons and azaleas. When planting in the garden, dig the ground over and make sure it is clear of weeds, then mix in a good handful of bonemeal per square metre. Space plants about 12-18in apart. Plant in groups of five or more for a bigger impact."
What the specialists say
David Edge, owner, Forest Edge Nurseries, Dorset
"Although heathers had gone out of fashion over recent years they are now making a comeback because they retain all their original qualities of being long-flowering, low-maintenance, ground cover and environmentally friendly to bees and other insects.
"Many heathers are now utilised for seasonal container planting and I am concerned that incorrect information is sometimes given out at garden centres, with customers not being steered towards ericaceous compost and not being informed that the winter/spring-flowering heathers can be planted in alkaline soils.
"There is currently a strong demand for the lower-growing forms of winter/spring-flowering heathers for garden planting, these being the varieties of E. carnea, over and above E. × darleyensis.
E. carnea varieties require a greater degree of attention in the growing cycle and are not so bold and bushy as their counterparts. Customers in this present day and age have smaller gardens and their requirements reflect on the type and ultimate size of plant required.
"I would recommend planting the winter/spring-flowering heathers because they are more robust and tolerant of soil conditions, albeit the extensive summer-flowering heather range provides for continuing sales throughout the summer and early autumn after the bedding season has diminished."
Species and varieties
Erica carnea is a hardy heather species that flowers from winter into early spring and can be grown on acid or slightly alkaline (chalky) soils. Most carnea are prostrate in habit and grow quickly.
E. carnea ‘Challenger’ Award of Garden Merit (AGM) (H7) is a prostrate evergreen shrub that forms a wide mat of dark foliage and has magenta flowers with contrasting crimson sepals. Height: 15cm.
E. carnea f. alba ‘Golden Starlet’ AGM (H7) is a neat variety with a spreading habit, producing white flowers from December to March. Its foliage is lime-green in winter, turning golden yellow in summer. Height: 10-15cm. Spread 30-45cm.
E. carnea f. alba ‘Isabell’ AGM (H7) is a spreading heather with erect shoots, producing bright-green foliage and racemes of white flowers in late winter and early spring. Height: 15cm.
E. carnea f. aureifolia ‘Westwood Yellow’ AGM (H7) is a compact, prostrate evergreen shrub with foliage that stays golden yellow throughout the year and produces shell pink flowers from late winter that gradually darken. Less prone to foliage burn in spring than most other yellow-leaved winter heaths. Height: 10-15cm. Spread 25-30cm.
E. carnea ‘Rosalie’ AGM (H7) is a compact spreading heather that features dark bronze/green foliage and racemes of deep rosy pink flowers from midwinter to spring. Height: 15cm.
E. × darleyensis is a hardy heather species that flowers from winter into early spring and can be grown on acid or slightly alkaline (chalky) soils. The result of crossing E. carnea and E. erigena, the plants are generally more bushy and taller than the carpeting E. carnea. Most varieties have pink or cream tips of new growth in spring and bronze foliage in winter.
E. erigena — the Irish or Mediterranean heath — is a hardy heather species that flowers from winter into early spring and can be grown on acid or slightly alkaline (chalky) soils. They have a dense, bushy habit and taller varieties can reach up to around 5ft. Their honey-scented flowers are still blooming when E. carnea flowers have finished and they cope well in moist conditions.
E. erigena ‘Irish Dusk’ AGM (H5) is a compact evergreen dwarf shrub with an upright habit. Dark-green foliage and salmon-pink flowers from winter to spring. Height: 60cm.
E. × veitchii ‘Gold Tips’ AGM (H5) is a bushy evergreen shrub of upright habit with bright dark-green foliage tipped with yellow growth in spring. Produces large plumes of fragrant white flowers in winter and spring. Height: 1.5m. Spread: 1m.
Calluna vulgaris, also known as ling or Scotch heather, is one of the hardiest and most varied of the heathers. Size ranges greatly from small tufts to shrubs. They often have interesting foliage and flower from midsummer to late autumn.
C. vulgaris ‘Dark Star’ AGM (H7) is a compact spreading evergreen shrub with dark-green foliage and spikes of semi-double, bright-crimson flowers. Height: 20cm.
C. vulgaris ‘Spring Cream’ AGM (H7) is a vigorous spreading evergreen shrub with dark-green foliage tipped with cream in early summer. Long erect racemes of white flowers. Height: 35cm.
C. vulgaris ‘Tib’ AGM (H7) is a compact evergreen shrub with dark-green foliage and double
deep-pink flowers in short spikes. Height and spread: 50cm.
Daboecia cantabrica is a sprawling or compact shrub with dark-green and usually lavender flowers produced in summer to autumn. Height: 40cm. Spread: 70cm.
D. cantabrica ‘Waley’s Red’ AGM (H5) is a spreading, dwarf evergreen shrub with small, dark, glossy ovate leaves. Produces long racemes of bell-shaped magenta-purple flowers. Height and spread: 50cm.
D. × scotica is a hybrid of garden origin between D. cantabrica and D. azorica. A compact shrub with dark-green glossy leaves, smaller than those of D. cantabrica. Produces white-to-crimson flowers from summer to late autumn. Ideal for ground cover in smaller gardens and for use in tubs, troughs and hanging baskets. Height 20cm. Spread: 45cm.
E. cinerea ‘Lime Soda’ AGM (H7) is a bushy plant with bright yellow/green foliage and spikes of mauve/pink flowers from early summer to autumn. Height: 30cm.
E. cinerea ‘Knap Hill Pink’ AGM (H7) is a dwarf evergreen shrub that forms a mat of dark foliage
and features magenta/pink flowers from midsummer to autumn. Height: 30cm.
E. tetralix f. alba ‘Alba Mollis’ AGM (H7) is a dwarf evergreen shrub with striking grey foliage and terminal umbels of nodding pure-white bells in summer and autumn.
E. vagans is a summer-flowering heather that will tolerate heavier soils and is generally described as moderately lime-tolerant.
Thank you to Floramedia, which supplied the images for this article from its photo library