How to Care for Heather Plants

Like a soft haze over a moor, heather (Calluna vulgaris) grows from 3 inches to 3 feet tall, with wispy foliage and racemes of 1/4-inch-long, urn-shaped white, pink or lavender flowers. Native to the United Kingdom and northern Europe, it blooms in midsummer to fall, with its foliage sometimes changing color in winter to warmer shades. Heather requires a site with full sun to part shade and acidic, well-drained soil -- with a pH between 4.5 and 5.5 -- in U.S. Department of Agriculture plant hardiness zones 4 to 10, depending on the cultivar. In cool, damp climates, the plant needs little care, but it may demand more attention elsewhere.

Watering can or garden hose

Peat moss or compost

Pruning shears

Bleach

Goggles

Respirator

Gloves

Protective clothing

Elemental sulfur

Ferrous sulfate

Neem oil

Spray can

Space your heathers about 12 to 18 inches apart in relaxed, natural-looking groupings of at least three plants rather than in straight rows.

Water your heathers frequently enough to keep the soil lightly damp, but not soggy.

Mulch around the plants with 2 inches of peat moss or compost to keep the soil cool and moist, and to suppress weeds. Avoid using a hoe to weed around these shallow-rooted plants. Keep the moss or compost at least a couple of inches back from the stems of the plants.

Refrain from fertilizing your heathers, as too much nitrogen can kill them. They should be able to obtain all the nutrients they need from the soil and mulch.

Prune your plants in early spring if you live in an area where freezing temperatures are common. In milder climates, prune your heathers in autumn, after they have finished blooming. In either case, simply trim off the withered racemes of flowers or the top 4 to 6 inches of growth on average-sized plants. Disinfect the blades of your shears between cuts by dipping them in a mix of 9 parts water and one part bleach.

Examine your heathers occasionally for signs of chlorosis, which is indicated by new foliage that is unnaturally yellow or almost white. Chlorosis generally is a sign that the soil is too alkaline, which you can verify with a soil test.

Scratch elemental sulfur into the ground to acidify the soil if the pH is higher than 5.5. Apply just one-half pound at a time to every 100 square feet. Wear goggles, a respirator, gloves and clothes that cover all your skin when you handle sulfur. Keep it off the foliage and work it very lightly into the surface of the soil to avoid disturbing the plants’ shallow roots. Wait at least four to six weeks before repeating the procedure. Continue that schedule until the soil reaches the desired pH, but apply the sulfur only during the warmest months of the year, as it is inactive in cold soil.

Spray your heathers monthly with ferrous sulfate during the growing season, to help the plants maintain their correct color while you're waiting for the slow-acting sulfur to take effect. Add 1 ounce of the ferrous sulfate to each 1 gallon of water. Protect your eyes, lungs and skin by wearing goggles, gloves, protective clothing and a respirator. Wet the foliage thoroughly in the morning, so that it will have time to dry before nightfall.

Saturate the heather plants with neem oil if you observe insect or fungus problems, including scale, spider mites, rust or powdery mildew. Scale insects look like brown bumps, spider mites like moving dust specks, and rust like red spores. Powdery mildew in heather often manifests as reddish shoot tips rather than the typical white spores. Spray the plants in the morning with a solution containing 2 tablespoons of neem oil mixed with 1 gallon of water. Even though neem is considered organic, it's best to wear protective clothing, goggles, gloves and a respirator when you apply the spray to avoid irritation to your skin or lungs. Repeat the treatment every seven to 14 days, depending on the severity of the problem, until the bugs or fungi are gone.

Heathers are more likely to suffer from fungal diseases in hot climates.

Heather plants are highly toxic and should never be consumed.

Heathers are considered invasive in some areas; contact your County Extension office for more information.