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Boronia parviflora

Swamp Boronia, Small Boronia, Small-flowered Boronia

Family: Rutaceae

A low growing shrub to a height of 1 m with hairless branchlets.

It occurs naturally in coastal and near-coastal areas with disjunct populations scattered along the east coast, from the north in Fraser Island Qld, down to around Grafton in NSW, then with a gap to South-West Rocks, then around Taree through to Sydney, extending to Katoomba-area, with a disjunction to Wollongong and Jervis Bay. Interestingly, plants are found again in north-eastern Victoria very close to the border with NSW, extending along the Victorian coast to South Australia, and also growing commonly in Tasmania.

It is found in shrubby swamps and wet heath, mainly on boggy sands.

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, the leaves are simple (or uni-foliolate), elliptic to ovate, to 30 mm long and to 7 mm wide with fine teeth along the edges, with the lower side of the leaf often having red tones.

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, the flowers are arranged singly or in groups of up to three in the upper leaf axils, bright to pale pink, occurring from August to March. Flowers are generally of a small size. Interestingly, it is reported that flowers have eight stamens in plants found in Queensland, New South Wales and Tasmania but sometimes only four or six in those of western Victoria and South Australia.

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

The fruit is to 4 mm long and to 3 mm wide.

In the garden

Not much is currently known about the cultivation of this species and it may be difficult to grow. It is found in swampy conditions and so may need a moist sandy soil to thrive. It may be cultivated more often in the future. It may be a boronia that is less fussy about good drainage perhaps.

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.

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.

Propagation

Boronias can be propagated from cutting but overall you will have 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

Boronia spp. are likely killed in bushfire 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.
parviflora – Latin – parvus meaning “small” and -florus meaning “-flowered”, referring to the small flowers of the species.

This species is not considered to be at risk of extinction in the wild.

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

Wikipedia – Boronia and Boronia parviflora Profile Pages
https://en.wikipedia.org/wiki/Boronia
https://en.wikipedia.org/wiki/Boronia_parviflora

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

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

Wrigley, J.W. & Fagg, M.I. (2001). Australian Native Plants – Propagation, cultivation and use in landscaping. 4th edition. New Holland Publishers, Pty. Ltd. Australia.

By Jeff Howes, edited Dan Clarke