Erica irbyana is an erect shrublet reaching 50 cm in height. The plant grows branched, wiry stems to 45 cm.
The narrow, needle-like and hairless leaves are grown in whorls of three. They may spread or press against the stems; in this case the latter. Leaf tips end abruptly with tiny central mucro-like protrusions are present as continuations of the midribs. The leaf margins are minutely gland-toothed.
One to eight stalked flowers emerge from the same point at a stem tip in umbel shape. The vase-shaped, pink to pale pink corollas taper in deeper colour to the constricted throats, then abruptly spread somewhat pointed, star-shaped lobes around the mouths. The dark red, acutely pointed sepals contrast against the pink bases of the corollas in the photo. The corollas are sticky. The eight anthers in each flower do not protrude above the flower mouth.
Flowering commences in spring and continues to midsummer. The photo was taken in December.
E. irbyana flowers show some variability. They are darker in the eastern part of the distribution range. The species resembles E. shannonea or E. shannonii, almost like a smaller version of it.
The species distribution is in the southwest of the Western Cape, only around Caledon, Hermanus and Bredasdorp. The photo is of a Fernkloof plant.
The habitat is lower fynbos slopes. The habitat population is deemed of least concern early in the twenty first century (Manning and Helme, 2024; Bean and Johns, 2005; Baker and Oliver, 1967; iNaturalist; http://redlist.sanbi.org).