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Boronia deanei

Deane’s Boronia

Family: Rutaceae

An erect and spreading shrub to 1.5 metres tall, spreading to 2 metres wide.

It has a distribution made up of a small number of disjunct populations, on the tablelands-coastal divide of NSW; occurring just north of Lithgow (Newnes Plateau), then at Fitzroy Falls and south-east of Robertson, then south near Nerriga (Morton National Park) and further south in Nalbangle NP (close to the Victorian border).

It grows in wet heath in boggy sandy soil and it is listed as being threatened with extinction in the wild.

The branchlets are covered with small wart-like projections

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 pleasantly aromatic, and appear as simple (or a compound leaf with 1 leaflet), in opposite pairs, terete to linear-obovate, to 12 mm long and 2 mm wide with warty projections on the undersides.

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, mostly close to the branch terminals, solitarily or up to 3 per group, white to bright pink occurring in August 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.

The cocci are hairless and occur in December.

 

In the garden

This species is a very attractive plant, especially when they are seen in their full glory in the wild.

It can be cultivated if plants can be sourced and a tip is given to grow in a pot.

It has proven to be a reliable and adaptable garden plant which can be grown in poorly-drained soils and is relatively frost-hardy. Its pleasantly-scented leaves and pink flowers are attractive features. Specimens have been grown successfully in pots. At the Australian National Botanic Gardens, plants have grown to a height of 2 metres, needing only tip pruning, occasional fertilising and adequate summer watering.

Observations have been made that it may be less fussy regarding drainage and soil type compared to other boronias. It is not commonly cultivated. However, it has been cultivated for a while with some good success.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 cuttings but with limited success with most but not all species.

Other information

There are two subspecies currently recognised in NSW:
Boronia deanei subsp. deanei – which has leaflets with a blunt tip;
Boronia deanei subsp. acutifolia – which has leaflets with a pointed tip

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 – 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.
deanei – after Henry Deane (1874-1924), a railway engineer, scientist and botanist. Deane carried out much work on fossil-flora in Australia. He published many papers, often with Joseph Henry Maiden, on botany and paleontology and made a special study of Australian timbers (Eucalyptus deanei was also named after him). He was president of the Linnean Society of New South Wales and of the local Royal Society and a fellow of the Linnean, (Royal) Meteorological and Royal Horticultural societies, London.

This species is listed as being threatened with extinction in the wild at both the State and Commonwealth level, with the category of Vulnerable.

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

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

NSW Office of Environment and Heritage – Boronia deanei profile page
https://www.environment.nsw.gov.au/threatenedSpeciesApp/profile.aspx?id=10097

Australian National Botanic Gardens – Boronia deanei profile page
https://www.anbg.gov.au/gnp/gnp9/boronia-deanei.html
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