Prostanthera rotundifolia Variegata

Prostanthera rotundifolia 'Variegata', sometimes called the Australian Mint Bush because of its origins, is a frost-tender shrub, which is well adapted to dry and poor soils. It forms a clear, rounded mass, with small leaves of olive green or slightly greyish-green, variegated with cream. Its highly aromatic foliage is not its only asset, because in spring, it is covered with a multitude of small tubular flowers, gathered in violet clusters. Its flowering lasts for several weeks in generous abundance. This shrub can be grown in the ground in mild Mediterranean zones and will also adapt well to pot cultivation elsewhere, so it can be brought indoors during cold periods.

Prostanthera rotundifolia is native to eastern Australia, New South Wales, Victoria, and Tasmania. It is a plant that thrives in well-drained and dry soil, and also does well in oceanic climates, as evidenced by beautiful specimens planted in sheltered positions in some gardens in Cornwall. This highly branched bush has a rounded, slightly spreading habit, supported by slender, square-sectioned and villous branches. Its growth is quite fast in moist soil, a bit slower in dry and poor soil. The lifespan of this plant is about 6 to 8 years, including in its native lands. An adult specimen will reach an average height of 2 m (7ft) with a spread of 1.50 m (5ft).

The cultivar 'Variegata' is slightly less vigorous than the type, reaching a height of 1.50 to 1.80 m (5 to 6ft) with a spread of 1 m (3ft) to 1.20 m (4ft). Its evergreen foliage consists of small, simple, opposite, rounded to ovate leaves, measuring only 1 cm (1in) to 1.5 cm (1in) in length. They are olive green in colour, with variegation or rather a cream-white margin that runs along the leaf lamina, making the foliage even more decorative. Pleasing to the senses, it is also highly aromatic, releasing a very pleasant menthol fragrance when crushed. The flowering takes place in April-May and lasts for several weeks. The small bell-shaped flowers with 5 lobes are grouped in clusters of 5 to 7 cm (2 to 3in) in length. They emerge from the axils of reduced leaves, on lateral branches. The flowers vary between 0.5 and 1 cm (1in) in length in light violet to purple shades. The fruit is a small almond.

The Australian Mint is elegant and charming all year round with its beautifully marginated miniature leaves, which are particularly delightful in spring. The shrub is tolerant of soil conditions including sea spray and resistant to drought. It only dislikes the cold, which can make it disappear in temperatures below -5°C/-6°C if the soil is not sufficiently well-drained. It requires little maintenance and even prefers to be forgotten from time to time, especially in summer. Light annual pruning after flowering will help maintain its density. It will easily establish itself in gardens along the Atlantic or Mediterranean coast. It creates beautiful borders, along a wall, or in a well-drained flower bed, alongside plants that thrive in mild climates. Combine it with the magnificent Grevillea gracilis Clearview David with its long-lasting scarlet-red flowers, the astonishing Acacia baileyana Purpurea, a Mimosa with purple young shoots, to create a unique contrast with delicate charm, or the dazzling Ceanothus Dark Star with its incredibly blue flowers.