Boronia muelleri

Boronia muelleri, the Forest Boronia, is a highly flowering aromatic Australian bush that will delight enthusiasts of rare and exotic plants. From a distance, in spring and summer, it resembles a heath with its upright habit, delicate foliage, and hundreds of small pink flowers. Like heather, it prefers sandy, poor, and acidic soil, but the comparison ends there. It is a plant related to citrus trees, not very hardy, comfortable in soils that remain moist even in summer. If you have a garden located on the coast, this Boronia should thrive in the ground. As it performs very well in pots, gardeners in cooler climates can admire it on the terrace throughout the summer and bring it indoors in winter in a lightly heated greenhouse or conservatory.

Boronia muelleri (synonym B. pinnata var. muelleri) is a shrub in the Rutaceae family, just like citrus trees. It is native to the Australian states of Victoria and New South Wales. In the wild, it is found in forests, woods, and heathlands, on sandy and moist soils. Its species name, pinnata, refers to its small pinnate leaves, composed of very fine leaflets. It has fairly rapid growth, reaching its adult size in 3-4 years. This shrub, with an upright and generally oval habit, will reach approximately 1.50m (4ft 11in) in height and 1m (3ft 4in) in width in the ground, sometimes much larger depending on the growing conditions. It develops slender branches covered with warty glands. These branches bear leaves composed of 7 to 17 leaflets that release a pleasant fragrance when crushed. The flowering, particularly long-lasting, occurs in spring and summer. Numerous small flowers appear in the axils of the leaves, clustered in small groups of 10 to 15 units. They are small bell-shaped flowers composed of 4 waxy petals of varying shades of pink, which open in a star shape around a bouquet of yellow and villous stamens. During fruit formation, the petals close and persist for a long time, enclosing the fruit until it ripens. This specificity gives the illusion of an endless flowering period.

Boronia muelleri cannot withstand temperatures below -5/-6°C and does not tolerate limestone or dry or heavy soils. It likes sun, but not scorching, and appreciates having cool roots. Its requirements are clear and must be respected to succeed in its cultivation and enjoy its magnificent flowering. Outside of certain coastal, it is possible to grow it in a pot, where the substrate and wintering conditions can be controlled. In the garden, this forest Boronia can be associated, for example, with Galvezia speciosa, Gomphostigma virgatum, or Dieramas. On the terrace or balcony, it can be surrounded by Dark Blue Cape Plumbago, with its long-lasting blue flowers, a Tibouchina, or a Double-Flowered Common Myrtle.