By: Teo Spengler
Don’t let the name “Red Boronia” fool you. Boronia information makes it clear that this common name for Boronia heterophylla doesn’t necessarily describe the color of the flowers in which the shrub bears. This Australian native usually has flowers that are a brilliant shade of magenta pink. For tips for how to grow Red Boronia, read on.
Boronia is a genus of evergreen shrub that includes many varieties. The perennial species called Red Boronia, native to Western Australia, is beloved by gardeners for its showy blossoms. The foliage is a deep green and the pink flowers are shaped like tulips.
Red Boronia’s flowers are fragrant and sweet smelling. They make excellent cut flowers, and the bell-shaped flowers bloom from spring through early summer, attracting butterflies and bees. They are also magnets for other beneficial insects.
If you have seen Red Boronia plants and admired them, you may be interested in inviting this flowering beauty into your garden. Growing Red Boronia takes a little effort, but the frothy flowers make it worthwhile.
First, find the appropriate location for the plants. Remember that the shrubs get to 5 feet tall and some 3 to 4 feet wide, so you’ll want to find a spacious site. Red Boronia plants do not appreciate the wind. They can live a long time if you plant them in a wind-protected location. They also grow best in an area with dappled sunshine, part sun and part shade.
Plant these shrubs in well-drained soil for best results and keep the soil moist. Boronia is frost-tolerant, but it doesn’t like its roots to dry out too much. Protect the roots of the plant with heavy mulch. Some even suggest spreading rocks over the soil. But you’ll also have to irrigate regularly during dry periods. Keeping those roots moist is important.
Red Boronia grows fast from young plants into attractive rounded shrubs. As mentioned above, Boronia plant care includes providing water during the growing season. It also includes feeding the shrub in spring.
You’ll probably want your Red Boronia plants to grow into dense shrubs, so trimming has to be part of the program. You can deadhead or tip prune every year once the flowers fade. Regular pruning as part of Boronia plant care results in thicker foliage and more flowers.
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With brilliant red flowers in spring, Boronia heterophylla is one of the brightest of all of the Boronias. Originally grown as a landscaping plant, it has become a favourite with cut flower growers as well.
Its popular because it is fast growing, has very aromatic foliage, and wonderful fragrant, deep pink flowers
From Western Australia, the flowers are lightly perfumed and rather than red we would call them a deep pink.
This is one of the easier Boronias to grow. Give it a sheltered position, a well drained soil and cool root run and it will be long lived.
It is used for cut flowers, and can be pruned each year. The trick with pruning is not to prune back into the previous years growth, or into bare wood.
Boronia heterophylla – White Form
If the soil is well drained, and the plant is grown where it receives some protection from the hottest part of the day, Boronia heterophylla is fairly easy to grow.
This is species with a fairly upright growth habit, so it can be pruned to give it a more rounded or bushy shape. Simple tip pruning after flowering will help maintain a good bushy shape.
With some natural variation in flower colour, a white flowering form named ‘Moonglow’ is now also available for sale. Another named ‘Cameo’ has striped flowers.
Also look for ‘Ice Charlotte’, ‘Blue Waves’ and ‘Just Margaret’.
On seeing the Red or Kalgan Boronia (Boronia heterophylla) in vivid flower everyone may wish to have one, and may wonder if it is easy to obtain and grow. It may be bought from some nurseries dealing in native plants, and its popularity is established in gardens as an easily-grown medium shrub which will live a good number of years with simple care.
Like the Brown Boronia (B. megastigma) it is native to Western Australia, is more robust and has a sweet scent in both leaves and flowers, though less powerful than the better known species. When lingering over the scent a slightly bitter aroma is sometimes noticed recalling Rue, and other plants of this family (Rutaceae) to which Boronias belong.
Growth is dense, flexible and soft in all parts and quite hardy to local winter conditions. Drought and hot winds, however, are not tolerated, and adequate water must be given, especially in summer. lt is essential to keep the roots cool and as watering on bare soil will not do this in extreme heat a mulch must be used unless nearby plants provide shade. Making sure the ground is soaked first, several inches of leaf mould or compost should be put around the plant. Another method is to use sizeable flat rocks. These look attractive, and in fact a large rockery makes a fine setting for this subject with its roots protected it flourishes in full sun.
In habit it is evenly round or oval, quickly making a mature specimen which may be 1 m high when two years old from planting, and eventually reaching over 1.3 m high. Healthy foliage has a fresh appearance all the year and individual leaves may vary on one plant from narrow and simple to finely divided.
From the leaf axils the squarish waxy bell flowers hang on short stalks, in clusters of two or three or singly. They appear around the third week of October and are a brilliant magenta pink, an unusual colour among shrubs at this season. On fading they close again to look like pointed buds and turn paler pink and white this colour holds till around mid-December in a cool spring. They finally fall, and seed has not been found here. Propagation is easy from cuttings, using young stem tips at a half-ripe stage. Plants succeed in any lime-free soil, light or heavy. Pruning is another operation which should be done regularly to keep up bushy growth, and if desired this may be combined with cutting freely for decoration. This is a good time to prune as before flowering is over new growth is starting which would be lost if pruned later. No serious pest or diseases have been noted.
Boronia - after an Italian, F. Borone who accompanied expeditions in the 18th century
Boronia heterophylla is a shrub which grows to a height of 1–3 m (3–10 ft) and has slender branches. The leaves are usually trifoliate with linear leaflets 20–30 mm (0.8–1 in) long on a petiole 20–30 mm (0.8–1 in) long. The leaves are only rarely simple. The flowers are deep pink to red and arranged singly in leaf axils on a thin, top-shaped, hanging pedicel about 10 mm (0.4 in) long. The four sepals are more or less round with a pointed tip and 2–3 mm (0.08–0.1 in) long. The four petals are about 8 mm (0.3 in) long and hairy on the inner side. The eight stamens alternate in length. The stamens near the sepals are black, sterile and about 1.2 mm (0.05 in) long and the ones near the petals are fertile but only about 0.5 mm (0.02 in) long. Flowering from September to November. 
Boronia heterophylla was first formally described in 1860 by Ferdinand von Mueller and the description was published in Fragmenta phytographiae Australiae.   The specific epithet (heterophylla) is derived from the ancient Greek words heteros ( ἕτερος ) meaning "different" and phyllon ( φύλλον ) meaning "leaf",  referring to the variable leaves. 
The red boronia is usually found growing near streams between Busselton and Albany in the Esperance Plains, Jarrah Forest, Swan Coastal Plain and Warren biogeographic regions of Western Australia. 
Boronia heterophylla is listed as "not threatened" by the Government of Western Australia Department of Parks and Wildlife.