Heather (Calluna and Erica genera) is a versatile, low-maintenance evergreen shrub valued for its year-round appeal. Common species, such as Calluna vulgaris (Scotch Heather) and various Erica species (Heaths), offer foliage colors that change seasonally, providing winter interest. These hardy plants form dense, compact groundcover mats that suppress weeds and thrive in poor, rocky conditions, provided they receive environmental conditions mimicking their native moorland habitats.
Selecting the Ideal Site and Soil
Heather requires a location that receives full sunlight for at least six hours daily to ensure vigorous growth and the most vibrant foliage and flower colors. While some varieties tolerate light partial shade, insufficient light will cause the plant to become spindly and reduce the intensity of its blooms and leaf pigments. In regions with extremely hot summers, morning sun followed by a little afternoon shade is often beneficial to prevent scorching.
The most important factor for heather health is the soil composition, which must be acidic, generally falling within a pH range of 4.5 to 5.5. Most Calluna species and many Erica varieties will exhibit yellowing foliage, a sign of chlorosis, if the soil is too alkaline or chalky. Amending the planting area with acidic organic matter, such as leaf mold or pine needles, helps to maintain the proper pH balance.
Excellent soil drainage is necessary; heather will not tolerate “wet feet” and is highly susceptible to root rot in soggy conditions. If the native soil is heavy clay, improve drainage by incorporating coarse sand or horticultural grit into the planting area. Ensure adequate spacing between plants to promote good air circulation, which reduces the risk of fungal diseases like powdery mildew.
Planting Procedures
The best times to plant heather are in early spring after the threat of frost or in early autumn, allowing roots to establish before winter dormancy. Before placing the plant, gently tease or loosen the roots from the root ball, especially if they appear tightly coiled. This encourages them to spread into the surrounding soil and prevents the plant from remaining root-bound.
The planting hole should be dug approximately twice as wide as the root ball but only as deep. This wider hole provides loosened soil that developing roots can easily penetrate laterally, leading to quicker establishment. Place the heather so the top of the root ball is level with or slightly above the surrounding soil grade.
Planting the heather slightly high helps to prevent water from collecting around the crown, which is a common cause of fungal issues. After backfilling the hole with the amended soil, firm the area gently with your hands to remove any large air pockets. The final step is to water the newly planted heather deeply and thoroughly, settling the soil around the roots and reducing transplant shock.
Routine Care and Pruning
Newly planted heather requires consistent moisture for the first year to develop a strong root system, necessitating regular watering until the plant is established. Once settled, heather becomes quite drought-tolerant, only requiring supplemental water during extended dry spells, although container-grown specimens will need more frequent hydration. A layer of acidic mulch, such as shredded bark or pine straw, applied around the base helps retain soil moisture and suppress weed growth.
Fertilization is rarely necessary for established heather, as they naturally thrive in nutrient-poor soils. Excessive nitrogen can lead to weak, leggy growth prone to winter damage and disease. If the plant is struggling or foliage indicates a nutrient deficiency, apply a very light amount of slow-release, acid-specific fertilizer in early spring. Keep the planting area clear of weeds, preferably by hand-pulling, to avoid disturbing the shallow root systems.
Pruning is the most important maintenance task for maintaining a dense, attractive heather form and preventing the plant from becoming woody and bare at the center. The timing of pruning depends on the species: summer-blooming Calluna vulgaris should be pruned immediately after the flowers fade in late fall or early spring. Winter-blooming Erica carnea varieties should be pruned right after they finish flowering in the spring.
The technique involves lightly shearing the plant, removing spent flower heads and only the top few inches of growth. Avoid cutting down into the old, leafless, brown wood, as heather will not regenerate new growth from these stems. Annual pruning encourages dense, bushy new growth, ensures prolific flowering, and preserves the plant’s compact groundcover habit.