Erica mammosa should be planted in a sunny position with well-drained, sandy, acidic soil (pH 5 to 6.5). Avoid warm humid conditions and ensure that the area in which it has been planted has good air movement. Feed and mulch with well-rotted compost. Mulching the area around the shrub will keep the roots cool and suppress weeds. Do not disturb the roots as they are very sensitive. Protect the plant from extreme cold and frost. Pruning of the shrub should be done to remove diseased material and ensure healthy, multistemmed growth.

Erica mammosa can be propagated by cuttings or seed. A faster result is obtained from cuttings. Take semi-hardwood tip or heel cuttings, about 40-50 mm long, in late summer to autumn. Treat the cuttings with a rooting hormone and place in a well-drained, well-aerated rooting medium; preferably 50 % crushed pine bark and 50 % polystyrene. Place the cuttings in a mist unit with bottom heating of 22-24°C. Good air circulation will reduce fungal infection. Rooted cuttings should be handled with care as the roots are fine and are very sensitive to any disturbance.

Seeds can be harvested when they start to fall out of the flowers naturally. To harvest, cut off the older flowers before they shed their seeds, dry them, and extract the seeds by rubbing the dried flowers against a rough surface; clean them using graduated sieves. Sow seeds in autumn (April to May) into a tray not less than 100 mm deep. The sowing medium should be well drained and acidic, levelled and firmed down. Seeds should be sown evenly to prevent damping off and fungal diseases. This can be achieved by mixing the seeds with fine sand before sowing. Seeds can be smoke treated before or after sowing. To ensure maximum germination, night and day temperature fluctuation should be approx. 8-10°C (16 hours of night) and 15-25°C (8 hours of day), the same as those that occur in the Western Cape during autumn.