Prostanthera ovalifolia Variegata - Mint Bush

Prostanthera ovalifolia Variegata, sometimes called Australian Bush Mint due to its origins or Variegated thousand flowered mint-bush for the wonderful colour and fragrance of its foliage, is a frost-tender shrub well adapted to seaside gardens. It forms a rounded but delicate plant, woven with small green-grey leaves edged with cream-white, and becomes spectacular in spring, disappearing under a multitude of small tubular flowers, gathered in blue-purple clusters. With a somewhat indefinable charm, it deserves to be seen and smelled up close and will undoubtedly win over the curious visitor, touched by its sometimes fragile appearance. 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;  regular watering could kill it as surely as a hard frost!

Prostanthera ovalifolia, which means oval-leaved, is native to eastern Australia, specifically New South Wales and Queensland. It prefers a rather acidic, well-drained soil, and also thrives 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, hairy branches. Its growth is quite fast in moist soil, a little slower in dry and poor soil. The lifespan of this plant is about 6 to 8 years, including in its native habitat. An adult specimen will reach an average height of 2.10m (7ft) with a spread of 1.40m. Its evergreen foliage consists of small, simple, opposite, ovate, toothed leaves, measuring 5 to 40mm (1 to 2in) long and 3 to 10mm (1in) wide. They are thick, dark green with a cream margin, but covered with white hairs which give them a more greyish hue, especially in hot and dry climates. When crushed, they release a pleasant menthol scent. The remarkably abundant flowering takes place from April to June, depending on the climate. The small bell-shaped flowers with 5 lobes are grouped in clusters 5 to 7cm (2 to 3in) long. They emerge from reduced leaves on lateral branches. The flower size varies between 0.5 and 1cm (1in) long and its colour is intermediate between light blue-violet and mauve. The fruit is a small almond.

The Variegated Australian Bush Mint is elegant and especially lovely in spring. The shrub is fairly tolerant of soil conditions, tolerates drought quite well, and is not afraid of salt spray. Its only enemy is cold, damp weather, which can make it disappear in temperatures as low as -7°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. A light annual pruning after flowering is more than enough. It will easily thrive in coastal gardens. It makes beautiful hedges, enjoys being against a wall, and stands out in shrub borders. It can be paired with evergreen Melaleucas, Gomphostigma, Leptospermum, and not-too-tall persistent Ceanothus (Italian Skies, Concha, Victoria). Mimosas, Leucophyllum, Raphiolepis, Oleander, Callistemon, or Grevillea can also accompany it in a dry or coastal garden. The choice is vast, it's all a matter of taste. Growing it in a container, allows the shrub to overwinter in a cold greenhouse or a very bright and minimally heated conservatory in very cold regions.