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Cyanothamnus anemonifolius

Narrow-leaved Boronia, Sticky Boronia

Family: Rutaceae

A shrub growing to 2.5 metres tall, often much smaller, and it can spread to more than 1 metre wide.

It occurs along most of the NSW Tablelands / Coast divide, growing on the northern tablelands and north coast areas, north from about Nundle, extending into south-east Queensland, then with a disjunction to the central and southern tablelands and coast areas, south from around Kandos, extending into eastern and central Victoria and Tasmania.

It is typically found in heath and dry sclerophyll forest and woodland, usually growing in rocky areas (granite, conglomerate and sandstone)

It has pimply / wart-like glands on its branches.

Cyanothamnus spp. produce opposite leaves which can be simple or compound (sometimes on the same plant) and are usually aromatic (sometimes strongly-so). In this species, leaves are compound-trifoliolate to pinnate with 3 to 5 leaflets. Overall leaves are up to 30 mm long, with obvious oil glands (glandular warts), aromatic when crushed. The leaflets are linear-oblong to linear-cuneate with a tri-lobed or entire apex

Cyanothamnus have complete flowers (bisexual and with all whorls present). The flowers are produced either solitarily or in groups, in the leaf axils, or, at the branch terminals. There are usually four sepals, four petals and generally eight stamens, surrounding one female part (carpel). Flowers are often pink to purple, which makes them easily identifiable in NSW bushland.

In this species, the flowers are white to pale pink and are arranged singly or in groups of up to nine in leaf axils, occurring from August to April

The fruit of Cyanothamnus are described as a schizocarp-capsule; a capsule that splits into even segments, which each segment called a coccus. In this species, capsules are hairless, to 5 mm long and 2 mm wide.

In the garden

This plant is known to be cultivated and can perform quite well if plants establish successfully. It is also mentioned on several international websites and so may be grown overseas as well.

In a garden situation, it blooms abundantly and can create a ground-covering sprawling shrub.

It performs best in sandy or other well-drained soil. Provide regular watering and ensure drainage is adequate. A slight slope may work best. It is moderately frost-tolerant once established.

Use as a border plant or in an open space where it can be admired. Prune lightly after flowering to encourage a dense habit and better flowering.

Growing boronias (including Cyanothamnus) can be a frustrating experience and they have a reputation for being difficult. Their attractiveness has led to substantial efforts to cultivate them. One tip is to try to grow forms that are local to your area, rather than attempting to grow those species from interstate. There are certainly some species that have proven easier to grow than others.

For them to grow at their best, select a position with dappled sunlight and especially protection from hot afternoon sun in summer, as well as from wind, which they dislike.

The soil must be well drained and have an even supply of moisture. If they dry out, they will surely die.

Planting on a slight slope is said to work well.

For a longer life, the best way to grow them is in a medium sized pot, say 30 cm in diameter where drainage and moisture can be controlled. A sheltered patio or courtyard that receives at least a few hours sunlight a day would be ideal

Fertilise after flowering.

The conventional wisdom is, think deeply about which species to plant and the location to plant it.
Boronias (including Cyanothamnus) can be propagated from cuttings but with limited success with most but not all species.

Propagation

Other information

This species is known by the synonyms:
Boronia anemonifolia
Boronia polygalifolia var. anemonifolia

There are four recognised subspecies, with 3 of these occurring in NSW:
Cyanothamnus anemonifolius subspecies anemonifolius – growing over most of the southern range, it has moderately hairy trifoliolate leaves and the petals persist in the fruit
Cyanothamnus anemonifolius subspecies variabilis is the most widely distributed subspecies, occurring in south-east Queensland, on the coast and ranges of New South Wales and in northern and south-eastern Tasmania. Leaves can have 5 leaflets and do not have hairs. The petals do not persist in the fruit
Cyanothamnus anemonifolius subspecies wadbilligensis grows in eucalypt woodland or low heath on rocky outcrops and is only found on the Wadbilliga plateau in New South Wales, south-east of Cooma. Leaves are densely hairy, with 3 to 5 leaflets.

Cyanothamnus is a genus of about 25 species, occurring in most states.
Several NSW species of Boronia have been transferred to this genus in 2020.

Most Cyanothamnus species would die in a fire and likely regenerate from the seedbank.

Cyanothamnus – cyano from Ancient Greek. kuáneos meaning “dark blue” and -thamnus (Θάμνος) meaning “bush” or “shrub” – referring to many species in the genus having blue flowers.
anemonifolius – is a reference to the similarity of the leaves of this species to those in the genus Anemone (a genus in the Ranunculaceae family, known as “windflowers”).

Not considered at risk in the wild – although one of the listed subspecies is considered rare.

Australian Native Plants Society Australia – Boronia profile page
http://anpsa.org.au/boronia9.html

NSW Flora Online (PlantNET) – Boronia anemonifolia profile page
https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Boronia~anemonifolia

Gardening with Angus Website – Boronia for Beginners and Boronia anemonifolia profile pages
https://www.gardeningwithangus.com.au/boronias-for-beginners-2/
https://www.gardeningwithangus.com.au/boronia-anemonifolia/

By Jeff Howes, edited Dan Clarke