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Growing Heathers and Heaths
The Basics
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.
Landscaping with Heather
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.)
Care and Maintenance
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.
Source:Better Homes & Gardens
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