Heather is a low-growing shrub that forms dense mats of foliage and color, defining the iconic appearance of moorlands and rugged landscapes across Northern Europe. This plant is a hardy evergreen that provides year-round texture and a spectacular burst of color in the late summer and fall, making it a popular choice for gardens. This article clarifies the identity of true heather, explores its distinct physical characteristics, and details the specific environmental requirements needed for successful cultivation.
Taxonomic Identity and Common Varieties
The plant most often referred to as “heather” is the single species Calluna vulgaris, commonly known as Scotch heather or ling. It belongs to the large flowering plant family Ericaceae, which also includes rhododendrons and blueberries. The name Calluna derives from the Greek word kallyno, meaning “to beautify” or “to sweep clean,” a reference to its historic use in making brooms.
A common point of confusion for gardeners is the distinction between Calluna and the closely related genus Erica, which is generally referred to as “heath.” Both share similar growth habits and environmental preferences, but they are separate genera. While Calluna vulgaris is the sole species in its genus, Erica includes hundreds of species, some marketed as “winter heathers” due to their earlier bloom times.
The two are primarily differentiated by their flower and leaf structure. Calluna has a four-part calyx that fully conceals the petals, while Erica typically has a five-part calyx and more pronounced petals. Within Calluna vulgaris, there are over 800 named cultivars, offering a wide palette of foliage and bloom colors. These varieties can range from deep purple and pink to white flowers, with foliage that shifts from green to gold, silver, or bronze, often intensifying in color during the winter months.
Physical Characteristics and Seasonal Blooms
Calluna vulgaris grows as a low, woody, evergreen shrub, typically reaching a height of 8 to 24 inches. The growth habit is generally mounding or spreading, forming a dense, ground-covering mat that helps suppress weeds. The foliage provides year-round interest, consisting of minute, scale-like leaves that are borne in opposite pairs along the stems and often overlap.
The most notable feature of heather is its prolific flowering, which typically occurs from mid-summer into early autumn, earning it the name “summer heather.” The small, bell-like flowers cluster tightly along the upper portions of the stems in dense, spike-like arrangements called racemes. While the wild form is typically a mauve or purplish-pink, cultivars offer blooms in shades of white, pink, crimson, and deep purple. The flowers are a significant source of nectar, attracting bees and other beneficial insects.
Cultivation Needs and Environmental Requirements
Successful cultivation of heather depends on replicating its native moorland environment, which is characterized by specific soil and light conditions. The plant performs best when situated in full sun, receiving at least six hours of direct light daily, though it can tolerate light afternoon shade in hotter climates. Adequate sunlight is important not only for robust flowering but also for encouraging the most vibrant foliage colors in ornamental varieties.
The primary requirement for heather is highly acidic, well-draining soil, ideally with a pH range between 4.5 and 5.5. Heather is intolerant of alkaline or heavy clay soils, which can cause the foliage to turn yellow, a condition known as chlorosis, due to nutrient unavailability. Growers often amend the soil with ericaceous compost, peat moss, or sand to ensure a lean, humusy, and free-draining substrate that mimics its natural habitat.
Although heather is drought-tolerant once fully established, it requires consistent moisture during its first 18 to 24 months after planting to develop a strong root system. It is important to keep the soil moist but never soggy, as waterlogging can quickly lead to root rot. Pruning is necessary to maintain the plant’s dense shape and prevent it from becoming leggy or overly woody. This maintenance should be performed annually in the early spring, before new growth begins, by shearing off the spent flower spikes and about one-third of the green growth.