Plant Profiles Calothamnus

The Myrtle family contains many genera, one of which is Calothamnus (claw bush or net bush). There are around 40 species of this genus, all native to Western Australia and mostly found in the extreme south-west although some species occur in the arid inland areas. Characteristics of the genus include the one-sided flower spikes and fusion of the stamen filaments into straps which may be narrow or broad. This has given rise to the name ‘net bush’. The term ‘claw bush’ originated from more fully fused, and curved, filaments.  All species of this genus attract birdlife.

The flowering season is normally from late winter to spring. The foliage may be needle-like, but can be flat, thick or narrow, depending on the species. The fruiting capsules may stay on the plants for some years becoming progressively more woody. In some individuals (human), Calothamnus can cause severe allergic reactions following contact with the plant.

Calothamnus gilesii or Giles’ net bush grows to 4.5 metres. It occurs in the wild in the semi-arid heathlands of Western Australia. The branches are upright and the long leaves pointed and covered in prominent oil glands. It has clusters of 3 or 4 bright red flowers from winter through to summer. It is a bird-attracting plant.

Calothamnus pinifolius is a small shrub with hairy branches. It occurs naturally only in Fitzgerald River National Park on the south coast of Western Australia. The leaves are stiff and needle-like and are crowded along the branches. Dense, long clusters of curved red flowers are produced from spring to early summer. Following flowering, globular capsules form along the stems.

Another species endemic to Fitzgerald River National Park, and more specifically to Barrens Range, is Calothamnus validus or Barrens claw flower. It is easily grown and a vigorous grower. It may be upright or rounded in habit and has thick branches and needle-like leaves. The flowers are large and red with only a few in each cluster. The flowers are held below the leaves and are followed by large woody capsules.

Calothamnus quadrifidus (common net-bush or one-sided bottlebrush) grows to 4 metres. It can be variable in habit with narrow grey to grey-green leaves. Red flowers appear from October to March. The flowers may be one sided spikes or may encircle the stems. It tolerates a range of conditions including both wet and dry soils. The plant is also attractive to birds.

This genus needs a light, gritty, well-drained soil. Once established they are drought-tolerant and will cope with light frosts. They should be tip pruned as the old wood can be slow to shoot.