General Description:

Cyanothamnus is a genus of 23 species, many of which were previously included in Boronia. The genus was reinstated in 2020* and the reclassification has been accepted by Australian herbaria.  It has not yet (July 2025) been taken up in the Australian Plant Census but it is assumed that this will occur in a future update of the Census. The majority of species are found in the south-west of Western Australia.

Cyanothamnus anemonifolius (previously Boronia anemonifolia) is an erect shrub up to about 2 metres in height with wart-like glands on the branches.  The leaves are usually pinnate with 3–5 leaflets up to 9 mm long and 1.5 mm wide, but may also be simple or bipinnate.  They have prominent glands and emit a strong aroma when crushed. The white to pale pink flowers are 4-petalled of a star-like appearance and are well displayed singly or in clusters from the leaf axils. Flowering occurs from late winter to summer, sometimes extending into autumn.

There are four recognised subspecies which differ mainly in the leaf characteristics.

This species is a very attractive garden plant and seems to be more reliable in cultivation than most other ‘boronias’. It requires a well drained, moist soil preferably in semi shade and should not be allowed to dry out. Plants respond well to light pruning after flowering to maintain a bushy shape and promote better flowering.  It is also tolerant of moderate frosts once established.

In common with most members of the Rutaceae, propagation from seed is difficult but cuttings usually strike successfully from current season’s growth.

* Duretto, Marco F.; Heslewood, Margaret M. & Bayly, Michael J. (2020), “Boronia (Rutaceae) is polyphyletic: Reinstating Cyanothamnus and the problems associated with inappropriately defined outgroups”, Taxon, 69 (3): 481–499