Boronia is a large genus of shrubs with many recognized species. Mostly these plants, which are in the citrus family, are native to Australia.
Some species are sweetly fragrant and are popular garden plants. There are some varieties that have a less pleasant fragrance, such as the pink boronia.
This perennial shrub sometimes grows as a small tree.
History
Boronia gets its name from the Italian plant collector, Francesco Borone of the late 1700s. A suburb of Melbourne, in Australia is called Boronia because a boronia plant was found growing there.
Plant Facts
| Scientific name | Boronia pinnataBoronia megastigmaBoronia serrulata |
| Common names | Pink boronia, pinnate boroniaBrown boroniaNative rose |
| Genus | Boronia |
| Family | Rutaceae |
| Height | 2 to 3 feet (0.91 meters) |
| Width | 3 feet (1 m) |
| USDA Plant Hardiness Zone | Zones 9 to 11 |
| Native to | Australia |
| Blooming season | Spring, summer |
| Flower colors | Pink, brown-yellow, cherry red |
| Plant specific features | Often grown as a short-lived perennial due to difficulty in maintaining sustained performance. Fragrant blooms |
How to Plant and Grow a Boronia Bush
Before deciding on a species of boronia, try to crush and smell the leaves before purchase. This will help you decide whether the plant’s scent is pleasant or not.
Some have a licorice scent, others are citrus-smelling. But there are some varieties that have an unpleasant odor – not unlike that of a male cat marking his territory!
The right location is important when growing boronia.
When you plant the boronia, you should dig the hole twice as wide as the root ball. The plant needs to be planted at the same depth as the root ball.
A layer of small gravel around the base of the plant will aid drainage.
Water well after planting. An application of compost mulch will help with water retention.
Where to Plant
Despite their reputation as short-lived and difficult perennials, if you plant them with care, you can enjoy these shrubs for many seasons. Find a planting site that is sheltered from the wind and where it will receive part sun and part shade.
An alternative method to grow boronias is to plant them in a container. A pot should be at least twice the size of the purchased pot.
Choose a container made of terracotta because of its increased porosity. Excess water in the pot needs to be able to drain away, so consider raising it off the ground or sitting it on a layer of pebbles.
When to Plant
Plant in the spring before flowering commences.
Boronia Shrubs Care and Maintenance
Soil
Well-drained but moist soil. The soil can be slightly acidic and enriched with organic matter, keeping any mulch away from the roots. Boronias do not like high levels of humidity, either in the ground or in the air.
If the soil doesn’t drain adequately, the roots will rot, and you will lose the shrub. For this reason, you should avoid planting in clay soil.
Excessive air humidity encourages fungal spores that will attack the stems and crown of the plant. Again the plant will die.
Water
Boronia shrubs should not be allowed to dry out between watering. Their roots are shallow, and the plants can dry out very quickly.
The soil should be consistently moist but also well-drained. The roots will not tolerate sitting in water; or logged soil. Once flowering commences, it is especially important to water very regularly.
Fertilizer
These shrubs do not require fertilizer, but once the flowers have finished you can apply a small amount of slow-release fertilizer.
Sunlight
Plenty of sun is needed for boronia. But it requires some protection from the heat of the afternoon sun, so a position with dappled shade is ideal.
Pruning and Repotting
This is a perennial which produces lovely flowers on long stems. If you cut flowers regularly, you will encourage more flowers.
By cutting stems after flowering by about a third, you will encourage the shrub to produce new growth.
Propagating
Several boronia species can be propagated by taking ripe cuttings in the summer. Not all cuttings will be successful. The cuttings should be taken from the current season’s growth, which has become woody and no more than 4 inches or 10 cm in length.
Pests and diseases
There are many native Australian pests that can attack boronia. The most serious insect threat are nematodes and black beetle which should be controlled by the use of a designated insecticide.
Temperature and Humidity
Boronia grows best in warm, coastal areas, in a position that is sheltered from too much wind. In coastal areas, humidity levels are usually lower, and this is ideal for the boronia.
Other Uses for Boronia
Brown boronia is grown for the strong fragrance of its flowers. The foliage releases a high-value oil that can be used in aromatherapy and as an oil in massaging treatments.
If you crush the leaves in your fingers, you will find that it releases its scent. However, due to its very high cost and rarity, it is seldom used.
Types of Boronia You Can Grow
Although brown boronia is the most well-known and sweetest smelling, there are many varieties available to choose from.
Flower colors vary, as does the size of the plant. Some have long flower stems and are especially good for cut flowers.
From an ease of growing perspective, the boronia heterophylla and boronia megastigma are considered to be the easiest species to cultivate.
Conclusion
Many people discover a boronia, and immediately fall in love with the shrub. It is the combination of colorful flowers and fragrant scent that especially appeals.
The best way to enjoy this plant is to consider it a short-lived perennial. In this way, you will not be disappointed if it doesn’t survive too many seasons.
And, you may be lucky – with attention and care, and perhaps a little luck, it may thrive for years!
*image by Wirestock/depositphotos
