Boronias

How to choose boronias

Brown Boronia is the one grown for perfume: small cup shaped flowers, brown outside and yellow inside, on a fine leaved shrub about 1m tall. It is also the fussiest, and many gardeners keep it in a pot for a few good years. Bremer Boronia is taller, to about 2m, with pale yellow green bells and a much longer life in the garden. Blue Waves Boronia is a form of the Kalgan boronia, one of the hardier bell flowered species. For colour, Lipstick Boronia carries bright pink bells, and Super Dooper Boronia is a compact shrub with pink star flowers over a long season.

Where boronias grow

Boronias come from open forest and heath, where the roots sit in cool, moist but freely draining soil under light shade. They do well in the cooler and temperate parts of Australia: Melbourne, the Adelaide Hills, Sydney, Perth and the ranges, and Canberra with shelter from hard frost. Morning sun with afternoon shade suits them. They struggle in humid subtropical and tropical summers, and in heavy clay that stays wet. In Brisbane and further north, grow them in a pot of native potting mix and expect a shorter life.

They sit well beside other Australian native shrubs with the same needs, and brown boronia belongs on any list of fragrant plants.

Planting and spacing

Plant in autumn or early spring. Choose a spot sheltered from strong wind. In clay, build a raised bed or mound 30cm high rather than digging a hole that holds water. Space compact varieties 60cm to 80cm apart and taller species 1m to 1.2m apart. Do not tease out the roots: slide the plant from its pot, set it at the same depth and water in. Mulch with coarse bark, gravel or leaf litter to keep the roots cool. In containers, use a native potting mix. See plants for pots for other container choices.

Care basics

The whole skill with boronias is even moisture. Never let the root ball dry out completely in summer, and never leave it sitting in water. Feed lightly in spring with a low phosphorus native fertiliser. Tip prune by up to a third straight after flowering to keep the shrub dense, cutting only into leafy growth, as old bare wood rarely reshoots. Sudden collapse in summer is usually root rot from wet soil or a root ball that dried out. Our guide to the most fragrant plants for Australian gardens has more ideas for a scented garden.

Common questions

Which boronia has the strongest scent?

Brown boronia, Boronia megastigma. One plant near a door or path scents the air around it in late winter and spring.

Are boronias hard to grow?

They are particular rather than hard. Give them cool roots, steady moisture and sharp drainage and they perform. Wet clay and dried out pots are what kill them.

Can I grow boronias in pots?

Yes, and in humid or heavy soil areas a pot is the more reliable way. Use native potting mix, keep the pot out of hot afternoon sun and do not let it dry out.

How long do boronias live?

Brown boronia often lasts three to five years. Tougher species such as Bremer boronia can live a good deal longer in well drained soil.