Boronia Sm.

Commemorating Francesco Borone, 18th century Italian botanist.

Shrubs, or rarely small trees or herbs. Leaves opposite, rarely near-opposite or whorled, simple, with 1 leaflet, 3-19 or more leaflets or bipinnate, the leaflets entire or toothed, occasionally 3-lobed, the lateral leaflets opposite. Flower clusters axillary or terminal, sometimes solitary. Flowers bisexual, of 4 free sepals. Petals 4, free, sometimes persistent in fruit. Stamens 8, free. Ovary of 4 more or less free carpels, each with 2 ovules; styles united. Fruit of 1-4 units, the black seeds dispersed explosively.

Boronias are grown for their attractive, sometimes aromatic foliage and simple flowers; some have exquisite scents that are used in perfumery.They are becoming of increasing international importance as cut flowers.

The following are the more rarely cultivated species:

B. anemonifolia A. Cunn., Sticky Boronia, from E Australia which has 3 leaflets per leaf and axillary flowers in spring that are white or pink;

B. denticulata Sm. from WA which has simple flat leaves, the margins of which have small teeth and terminal, branching mauve to pink or white flower clusters in spring;

B. mollis Lindl., Soft Boronia, from NSW and available as 'Lorne Pride', a dense, compact, prolifically flowering form found originally at Lorne near Laurieton, NSW, and registered with ACRA in 1978;

B. molloyae Drumm., Tall Boronia, from WA, a shrub to 4 m tall with pinnate leaves and pendent, nearly closed flowers in spring and summer;

B. pilosa Labill., Hairy Boronia, from SA, Vic and Tas, available as the cultivar 'Rose Blossom', which is a smallish, compact shrub with double rose-like flowers; and

B. serrulata Sm., Native Rose (Sydney Rock Rose), a densely flowered species available in white as well as pink forms;

B. spathulata Lindl. from WA is available in a large-flowered form.

 

Most species by semi-hardwood cuttings, those from WA by seed.

Perfumery and as cut flowers in floristry.

Mostly shrubs; leaves opposite and decussate; petals 4, free; stamens 8; style terminal; fruit dry and dehiscent.

In 1997, 'Karwarra' in the Victorian Dandenongs had a collection of 76 different kinds, including over 20 cultivars.

148 species endemic to Australia.

Duretto (1999).

As the range of available boronias varies considerably from year to year, a key would be impractical.

Source: Spencer, R. (2002). Rutaceae. In: Spencer, R.. Horticultural Flora of South-eastern Australia. Volume 4. Flowering plants. Dicotyledons. Part 3. The identification of garden and cultivated plants. University of New South Wales Press.

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Cultivars of hybrid origin

A number of cultivars have been released by Yellow Rock Native Nursery, Winmalee, NSW, and Plant Growers Australia.

Boronia 'Aussie Rose'

Flowers prolific in the leaf axils in late winter to early spring.

A natural hybrid, B. serrulata x B. floribunda, from the Hawkesbury sandstone region N of Sydney and given to Ken Turnidge of Turnidge's Nursery, Galston, NSW, in 1982.

Introduced c. 1989.

Boronia 'Carousel'

Upright shrub to 2 m tall with fragrant flowers in mid-spring, the petals long-lasting, turning deep pink.

B. heterophylla x B. molloyae.

Introduced 1987.

Boronia 'Lipstick'

B. crassipes x B. heterophylla,

Collected by Yellow Rock Native Nursery, Winmalee, NSW, and introduced 1987.

Boronia 'Telopea Valley Star'

Released by Telopea Valley Nursery and registered by ACRA in 1980.

kingdom Plantae
phylum   Tracheophyta
class    Magnoliopsida
superorder     Rosanae
order      Sapindales
family       Rutaceae
Higher taxa
Subordinate taxa
species         Boronia heterophylla F.Muell.
species         Boronia megastigma Nees
species         Boronia muelleri (Benth.) Cheel
species         Boronia pinnata Sm.