Boronia

Caprifoliaceae

Boronia

 Boronias are mainly small shrubs. All have scented foliage, some unpleasant. They are noted for their scent, but only a few have highly perfumed flowers. They are generally fast growing but tend to be short lived (5 to 8 years).

 

Uses

Garden plants, container plants, oil extraction, cut flowers.

Culture

Boronias are particular in their growing requirements. Soils need to be light to medium, providing good drainage. Most Boronias dislike alkaline soils but seem to do best in infertile soils, particularly those lacking in nitrogen. Moisture is vital, the plants should never be allowed to dry out. They like to be moist but not wet as they can be susceptible to root-rot. Plenty of water should be provided in summer, on the leaves as well as the soil. They need a cool root area, as too much variation in ground temperature seems to disturb them and they don’t like too much heat. Root disturbance can upset them, therefore digging close to the plant’s shallow roots should be avoided. Generally overhead shelter from both the sun and frosts is important. In drier areas of the country, permanent semi-shade is needed for most types. They require protection from both hot and cold winds.

Growing requirements are also quite specific. A mulch of leaf-mould or some other acid organic material is beneficial once the plants are established. This helps to retain moisture and keep the roots cool. All mulches should not be allowed to touch the stem so as to avoid fungal infections.  Very light applications of genuine blood and bone or thoroughly rotted farmyard manure should be made at intervals. A fairly heavy pruning of strong plants should be made after the first flowering and a consistent light pruning after each following flowering.

Propagation

Cuttings usually preferred

Cultivars

Cultivated species include: 

B. denticulata - 2m high x 1m wide. Very hardy. Pink flowers all year.

B. filifolia - 50cm high x 1m wide. Cool, sunny spot. Pink flowers all year.

B. heterophylla - 2m high x 1m wide. Well drained, mulched soil. Red flowers in spring.

B. megastigma - 1m high x 1m wide. Short lived. Scented flowers. Grown as a cut flower. Brown/gold flowers early spring.

B. mollis - 1.5m high x 1m wide. Soft, divided foliage. Bright pink flowers.

B. muelleri - 50cm high x 50cm wide. Fern-like foliage. Pink flowers in spring.

B. pilosa - to 1m high x 60cm wide. Soft foliage. Pink flowers in spring.

B. pinnata - 1.5m high x 1m wide. Different foliage. Bright pink flowers in spring.

 

Plant Health

Can be susceptible to fungal diseases, root rots in particular.

More info

Boronias are uniquely Australian and are found throughout the country, commonly in coastal or open woodland areas. There are 95 types, with about half coming from Western Australia.

More from ACS