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Boronia angustisepala

Family: Rutaceae

An erect shrub, growing to 1.5 metres tall, spreading to about 1 metre wide.

It grows solely in and has a restricted distribution in NSW, with some disjunct populations occurring in the Kandos – Hunter Valley area, then growing west of Grafton, with some records at Coonabarabran and north-west of Narrabri.
It typically grows in dry sclerophyll woodlands and forests on sandstone and sandy soils.

It has branchlets covered with start-shaped (stellate) hairs.

Boronia 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-imparipinnate with 3 to 11 leaflets. Overall, leaves are up to 60 mm long, aromatic when crushed.
The leaflets are elliptic to spathulate, to 25 mm long and 10 mm wide with rounded apices, with hairs usually on either side.

Boronia 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, flowers are produced in leaf axils, either solitarily, or up to groups of 3, bright pink in colour, occurring from July to November.

The fruit of Boronia are described as a schizocarp-capsule; a capsule that splits into even segments, which each segment called a coccus.

In this species, the fruit are about 6 mm long and 3 mm wide with the remnants of the petals attached.

In the garden

This species is not currently well-known in cultivation. It may be difficult to grow or may not have been trialled to verify if cultivation is successful.

Growing boronias 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.

Most Boronias have a short life span of two to three years in a garden situation but are a rewarding plant while healthy as they provide lovely fragrance and flowers in Spring

Most boronias have a short life span of two to three years in a garden situation but are a rewarding plant while healthy as they provide lovely fragrance and flowers in Spring

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.

Plating 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.

Propagation

Boronias can be propagated from cuttings but with limited success with most but not all species.

Other information

Boronia is a genus of about 160 species of flowering plants in the citrus family Rutaceae. Most species are endemic to Australia and species can be found in all states. There are also some species in New Caledonia, which were previously placed in the genus Boronella.

Boronias are likely killed by fire and regenerate from the seedbank.

Boronia – after Francesco Borone (1769-1794), an 18th century Italian botanist who assisted John Sibthorpe. Allegedly, he died at age 25, due to falling out a window whilst collecting plant specimens.
angustisepala – Latin – angustus meaning “narrow” and -sepala meaning “sepal”, referring to the narrow sepals of this species.

Not considered at risk in the wild.

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

Wikipedia – Boronia angustisepala and Boronia profile pages
https://en.wikipedia.org/wiki/Boronia
https://en.wikipedia.org/wiki/Boronia_angustisepala

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

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

By Jeff Howes, edited Dan Clarke