Prostanthera rotundifolia Rosetta

The Prostanthera 'Rosetta' is a beautiful selection with pink flowers of a shrub called Australian Mint due to its origins or Tree Mint. Not very hardy, it is well adapted to coastal areas and dry, poor soils. It forms a rounded, light mass, and its small greyish-green leaves, pleasantly aromatic, are adorned in spring with a multitude of small bell-shaped flowers in clusters. To successfully grow it in a mild climate, remember that it does not like water in summer but appreciates partial shade, especially in hot climates; do not place it on the lawn; regular watering could kill it as surely as a hard frost!

The Prostanthera 'Rosetta' (syn. 'Rosette') is a horticultural selection. The genus Prostanthera (Mint-bush in English) includes about 90 Australian species belonging to the Lamiaceae family. They are not hardy plants that thrive in well-drained, dry soil and mild oceanic climates. 'Rosetta' is a highly branched shrub with a rounded, slightly spreading habit, supported by slender, villous, square-sectioned branches. Its growth is relatively fast in moist soil but slower in dry and poor soil. The lifespan of this plant is about 6 to 8 years. An adult specimen will reach an average height of 1.75m with a spread of 1.50m. Its evergreen foliage comprises small, simple, opposite, ovate leaves measuring 1cm to 2cm long. They are dark green but covered with white hairs, which give them a more greyish hue, especially in hot and dry climates. When crushed, they release a minty scent, delightful. Flowering occurs in April-May. The small bell-shaped flowers with five lobes are grouped in small clusters. They emerge from the axils of reduced leaves on the lateral branches. The size of the flower varies between 0.5 and 1cm in length, and its colouration is candy pink with a dark pink throat.

The Australian Mint Rosetta is elegant, discreet for much of the year, and delightful in spring. The shrub is tolerant of soil type, resistant to drought, and unafraid of salt spray. Its only enemy is the cold, which can make it disappear as soon as -5°C if the soil is not sufficiently well-drained. It requires little maintenance and occasionally prefers to be forgotten, especially in summer. A light annual pruning after flowering is sufficient. In gardens along the Atlantic or Mediterranean coast, it forms beautiful borders along a wall or pretty hedges, in the company of Melaleuca, Gomphostigma, Leptospermum, and evergreen Ceanothus that are not too tall (Italian Skies, Concha, Victoria). Westringia, Leucophyllum, Raphiolepis, Callistemons, or Grevilleas can accompany it in a dry or coastal garden. The choice is vast; it's all a matter of taste. Cultivating it in a container, sometimes delicate, allows the shrub to overwinter in a cold greenhouse or a very bright and minimally heated conservatory in very cold regions.