Erica brachialis is a long-lived plant. The oldest known wild plant, with a trunk diameter of 40 cm, is estimated to be at least 200–300 years old. This species also has the ability to resprout, not from an underground rootstock, but from the trunk or a stem. This is known as natural coppicing. It enables a plant to survive damage such as being broken or knocked over. One would expect that it would also give the plant an advantage when it comes to surviving fires, but in fynbos that is burned frequently field observations by Ross Turner show many adult and juvenile Erica brachialis plants are killed by fire, with most of the population growing in rocky areas that are less affected by fire.

Unlike many other ericas, Erica brachialis does not flower prolifically and thus does not produce large quantities of seed, which would allow it to recolonise the area after a fire more readily. All this shows that Erica brachialis does not cope very well with frequent fires. It also indicates that in the absence of frequent fires E. brachialis would colonise a wider area, i.e. not just favour the rocky areas but also move onto the open slopes.

E. brachialis flowers are pollinated by the Orangebreasted Sunbird (Anthobaphes violacea), which visits to feed on the nectar, and while feeding, pollinates the flowers.

E. brachialis is unusual among ericas in that it keeps its ovaries, and seeds, on the plant for a season, sometimes longer, before shedding its seeds. It does not develop a thick protective covering for the fruits, like serotinous species do. (Serotinous species retain their seeds on the plant, usually in woody fruits or cones, for more than a year after they are ripe. Some species retain them for up to ten years.) The ecological or evolutionary advantage of Erica brachialis retaining it seeds for a year or so has not been explored.