The boronias are members of the Rutaceae family in common with the widely cultivated native correas and croweas as well as the exotic citrus.
There are 140 species that are native to Australia. NSW is home to 28 species and of these, 10 are found in the New England region.
Boronias are characterised by aromatic foliage and colourful flowers. Blooms are four-petalled, sometimes star-like and sometimes bell-shaped. Boronias come in a range of flower colours including red, pink, yellowish-green, blue, white and brown.
They range is size from dwarf to tall shrubs. With judicious pruning, most boronias may be kept to a comfortable height of about 1m. Some species are grown for the cut flower trade.
Boronias prefer semi-shaded, well-drained sites. Plants should be well mulched to prevent drying out. As well using organic mulch, boronias could be grown surrounded by rocks to keep roots cool. After flowering they respond to light annual pruning.
Most boronias may be propagated from cuttings. Growing from seed is a trifle difficult.
Boronia crenulata is a delightful small plant that reaches a maximum height of 1m.
Boronia carousel comes from Western Australia and is a naturally occurring hybrid with obscure parentage. The hybrid has been in cultivation since 1987.
Carousel will reach a height of about 1.5m in local gardens. Divided leaves are aromatic, dark green and up to 35mm long. Flowers bell shaped, 8mm long, bright pink ageing to deep red and are both conspicuous and profuse. Flowering occurs from late September to November.
Boronia crenulata is a delightful small plant that reaches a maximum height of 1m. The leaves are spoon-shaped, about 1cm long and strongly aromatic. The flowers are pink and are carried for many months.
Boronia crenulata comes from Western Australia and could be cultivated in cottage gardens, rockeries or as a foreground plant in native garden beds. This boronia is sometimes marketed as "Pink Passion".
Boronia denticulata is an old favourite also from Western Australia. This is a tall shrub that may reach a height of 2m. Leaves are light green, narrow, aromatic with toothed margins. Flowers are star-shaped, bright pink and appear between August and November with sporadic flowers at other times. This is a handsome, hardy boronia that should be tip pruned occasionally to promote bushy growth.
Boronia pinnata is a common plant in the Sydney sandstone country. In the garden this species could be kept to a height of 1m. Aromatic leaves are about 25mm long with pairs of widely spaced leaflets. The profuse pink flowers are in clusters and appear in spring.
Boronia pinnata was an early horticultural export and was grown in English glasshouses in 1803.
Boronia heterophylla, the red or kalgan boronia, is a beautiful, medium shrub. Leaves are divided, aromatic and dark green. The bell-like flowers are profuse, fragrant and bright reddish pink. Blooms appear in October and usually held on the plant until December. This is one of the most colourful boronias and given the right conditions will live for many years in the garden.
There we have some boronias. Their aromatic foliage and flowers will bring perfume and colour to the garden.
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