When people mention heather, they are almost always talking about two different genera of plants: heaths and heathers. Although both belong to the Ericaceae family, they are botanically different and are divided into the Calluna genus and the Erica genus. For practical purposes, however, they are nearly identical, sharing color, form, and growth habits. They are all evergreen, well-mannered, and low-maintenance plants that thrive in similar conditions of sunlight, water, and soil. Winter hardiness is the only major difference between species.
All true heathers are cultivars of just one species, Calluna vulgaris (which some botanists erroneously classify as Erica vulgaris), and there are easily more than 500 varieties available. Most are summer-blooming, ranging from white to rose to deep purple, and their foliage is green to fire orange; their leaves are small and scalelike. Most form low-growing mounds or spreading mats. For the heather lover in the North, these are the plants of choice, as opposed to the true heaths, which offer more colors but are generally less hardy. Calluna are typically hardy in Zones 5-7 but may thrive as far north as Zone 3 with adequate winter protection or snow cover. These low, mounding shrubs are the ling of Scotland, the famous heather of the Highlands.
The true heaths belong to the Erica genus and include more than 700 species and countless cultivars, such as winter heath (Erica carnea), bell heath (Erica cinerea), Darley Dale heath (Erica x darleyensis), Cornish heath (Erica vagans), and cross-leaved heath (Erica tetralix). Hardiness ranges widely; for instance, Erica carnea will bloom under snow, but many of the South African varieties, such as blood-red heath (Erica cruenta), are best left to the greenhouse and florist trades. The true heaths offer an amazing range of foliage and bloom color, well beyond the pinks of the heathers; they also come in taller shrub forms and even some small trees. With hundreds of species and cultivars suitable for hardiness Zones 7-9 or 10 (and a few, such as Erica carnea, even hardier), the heaths provide a wide variety of colors and bloom times to fill Southern gardens.
Other than heaths' greater susceptibility to cold weather, the main difference between heaths and heathers is that heaths have needlelike leaves rather than flat leaves. The scalelike leaves of heather, in fact, feature tiny hairs, which give the foliage a grayish cast. Calluna cultivars also produce blooms where the corolla (or whorl of petals) is completely encased by the calyx (the usually green "leaves" directly beneath a bloom); the Erica species and varieties feature prominent corollas and small calyxes, which often create a two-tone effect to the blooms. However, the bloom shapes are so nearly the same, says Kate Herrick of Rock Spray Nursery in Truro, Massachusetts, "that only a botanist or a true fanatic will know the difference."
Of course, the real reason to plant heath or heather is the colorful bloom and foliage. Imagine Monet's palette loaded with hues of blue, yellow, gold, rose, and green. Imagine a painting built from brush strokes of tall shrubs, lush mounds, and spreading mats. Plant different types of heathers and heaths, and you can have a steady play of form and color as new plants come into bloom when others fade. Plant several varieties en masse on a slope, and an Impressionist's landscape bursts into vivid life.
As heather fans know, selecting plants by color isn't as simple as deciding you like pink blooms; selection by bloom color is actually secondary to the foliage display. A heather's evergreen foliage changes and intensifies in hue during cold weather. For example, Calluna vulgaris 'Firefly' has copper foliage in summer that changes to brick red in winter; Erica x watsonii 'Dawn' (a Watson's heath) has red spring growth that turns to gold later in the year. It is this variability that makes heaths and heathers such arresting plants for the landscape.
"There are so many colors available that selecting plants can be intimidating, and people often make the process more complicated than needed," Herrick says. The colors are so harmonious, however, that a homeowner should pay more attention to plant sizes and spacing, she advises. Selecting plants that will fill a designated space is easier to achieve than trying to work a plant of every bloom and foliage color into the scheme.
"They are a fascinating family of plants," Herrick sums up, "and a lot more fun than red geraniums." Try painting some into your landscape this fall.
Heaths and heathers add a low-maintenance jolt of color and interest to the landscape, regardless of the season. Their evergreen foliage (in shades of green, yellow, bronze, and red) sparkles against the weary winter backdrop of tans and browns or the white of snow.
Plant heaths and heathers in open areas, up hillsides, or along pathways. They pair especially well with dwarf conifers, which require similar acidic soil conditions. They tolerate poor, rocky soil and even salt spray, so they're marvelous along coastal hillsides where little else will grow.
Heaths grow about 1 foot tall by 1 1/2 feet wide; heathers about 2 feet tall by 2 to 3 feet wide. Space both about as far apart as their mature width and at least 2 feet away from other shrubs to foster good air circulation. For naturalistic mass plantings, Kate Herrick at Rock Spray Nursery suggests multiplying the square footage of your planting area by 0.44 to determine the number of heaths or heathers you'll need. (A 10-x-10-foot area would require 44 plants.)
The growing conditions for these colorful plants are similar. Karla Lortz of Heaths and Heathers Nursery offers these tips.
Prep the soil. Heaths and heathers are acid lovers, preferring a soil pH of 4.5-5.5. Although some heaths are more tolerant of alkaline soil, particularly Irish heath (Erica erigena), most types will struggle. Work in damp peat moss or other acidic soil amendments, particularly if your soil is pH neutral (6.5-7.5). Till or loosen the soil and dig holes twice as wide as each plant's root ball to encourage roots to spread.
Provide drainage. Without good drainage, these plants just won't grow. For clay soil (which provides neither the right pH nor proper drainage), build a raised bed with equal parts topsoil, sand, and composted bark or peat moss, which will create acidic soil that properly drains. For boggy soil (which may be the right pH but too wet), make a modest berm.
Plant. Shear newly purchased plants to encourage bushiness, and plant in spring or early autumn. Water twice a week for the first several months so the ground is moist but not soggy. This will encourage rapid, vigorous growth to get plants established. Apply a mulch of your choice, preferably an acidic one (such as pine straw, peat moss, or leaf mold). After two or three years, heathers and heaths are generally drought-tolerant and can take care of themselves.
Allow for spacing. Space the plants about as far apart as the plant's mature width to allow air circulation, which is important for good foliage growth and color but close enough so the plants will eventually mound together. If you are planting in Zones 7-9, Lortz recommends whorled heath (Erica manipuliflora; 'Korcula' is a good cultivar).
Consider sun exposure. Allow for a minimum of six hours of sun a day for best foliage effect. The foliage will be best on the south side of the plant, especially for red varieties. Six or more hours of sun are also recommended with afternoon shade in hotter areas. Too much shade makes the plants leggy and dulls the brilliance of those that have colorful foliage.
Consider winter exposure. Avoid situating plants in areas that receive harsh winter winds; as evergreens, they suffer severe dehydration. Or apply a winter mulch such as evergreen boughs. In areas with deep snow cover, plants will be fine.
Don't fuss. Heaths and heathers actually like poor soil. Giving annual doses of fertilizer is deadlier than not giving any at all. Fertilize once with rhododendron feed upon planting -- then leave your plants alone. About the only work you need to do is give them a yearly shearing. This is best done in the spring before any buds have set or, for winter bloomers, after the flowers have faded. Calluna vulgaris should be cut back below the old flowers; the Erica spp. can be lightly pruned to encourage bushiness.
Unless otherwise noted, heathers (Calluna vulgaris) are hardy in Zones 5-7 and are no more than 2 feet high and slightly more as wide.
CULTIVAR: 'Alba Rigida' Flowers: White Foliage: Bright green Characteristics: Spreading, very hardy in Maine trials (Zone 4)
CULTIVAR: 'Firefly' Flowers: Mauve Foliage: Brick red Characteristics: Excellent for foliage, upright growth
CULTIVAR: 'H.E. Beale' Flowers: Silver-pink Foliage: Bronze Characteristics: Double flower, upright growth
CULTIVAR: 'J.H. Hamilton' Flowers: Pink Foliage: Dark green Characteristics: Outstanding pink variety, double flower, dwarf habit
CULTIVAR: 'Mrs. Pat' Flowers: Light purple Foliage: Pink-tipped Characteristics: Good foliage all year, more difficult to establish than most
CULTIVAR: 'Spring Torch' Flowers: Mauve Foliage: Midgreen with yellow-orange to pinkish cream tips Characteristics: Upright growth, excellent foliage color
CULTIVAR:'Tenuis' Flowers: Lilac Foliage: Dark green Characteristics: Hardiest in Maine trials (Zone 4), early flowering, low growing
CULTIVAR: 'Tib' Flowers: Dark pink to purple Foliage: Dark green Characteristics: Double flower variety with long bloom time, bushy habit
CULTIVAR: 'Velvet Fascination' Flowers: White Foliage: Downy silver-gray Characteristics: Upright growth, excellent foliage quality
CULTIVAR: 'Winter Chocolate' Flowers: Lavender Foliage: Gold-pink to bronze-yellow Characteristics: Provides year-round color, compact plant
Heaths tolerate more heat than do heathers and are generally good choices for Southern regions, though they dislike extremely humid areas. Most species grow about 1 foot tall by 1 1/2 feet wide.
SPECIES/CULTIVAR: Erica carnea (winter heath)'Bell's Extra Special' Flowers: Purple-red Foliage: Gold-flecked Characteristics: Very hardy, tolerant of most soils, Zones 5-7 (Zone 3 with protection)
SPECIES/CULTIVAR: E. cinerea (bell heath) 'Velvet Night' Flowers: Purple-black Foliage: Dark green Characteristics: Spring to summer blooming, acidic soil, protect until established, Zones 6-8
SPECIES/CULTIVAR: E. x darleyensis (Darley Dale heath) 'White Perfection' Flowers: White Foliage: Bright green Characteristics: Early blooming, suitable for most soils, long spikes, Zones 7-8
SPECIES/CULTIVAR: E. erigena (Irish heath) 'Irish Dusk' Flowers: Salmon pink Foliage: Gray-green Characteristics: Compact, honey-scented, tolerates alkaline soil, Zones 8-9
SPECIES/CULTIVAR: E. lusitanica (Portuguese heath) Flowers: Pinkish white Foliage: Medium green Characteristics: Drought-tolerant, acidic soil, naturalizes well, Zones 8-10
SPECIES/CULTIVAR: E. manipuliflora (whorled heath) 'Korcula' Flowers: White, tinged pink Foliage: Gray-green Characteristics: Tolerates excessive heat and humidity, Zones 7-9
SPECIES/CULTIVAR: E. tetralix (cross-leaved heath) 'Pink Glow' Flowers: Magenta Foliage: Gray-green Characteristics: Compact, prefers boggy ground, acidic soil, Zones 5-7
SPECIES/CULTIVAR: E. vagans (Cornish heath) 'Mrs. D.F. Maxwell' Flowers: Rose pink Foliage: Dark green Characteristics: Tolerates alkaline soil, bushy, good for borders, Zones 7-9
SPECIES/CULTIVAR: E. x watsonii (Watson's heath) 'Pink Pacific' Flowers: Pink Foliage: Red with gold Characteristics: Good tip color, long-blooming, Zones 5-7
SPECIES/CULTIVAR: E. x williamsii (Williams' heath) 'P.D. Williams' Flowers: Rose to lilac pink Foliage: Gold-tipped green Characteristics: Tolerant of alkaline soils, spreading, summer blooming, Zones 5-7