The Mint Bush Family - Cultivation

Of the Australian members of the Lamiaceae, only Prostanthera and Westringia are in widespread cultivation. Species of Ajuga, Hemiandra and Plectanthus are seen from time to time but most other genera are only grown by collectors.

All species that are in general cultivation perform best in well-drained, moist soils but they rarely succeed in continually wet soils. Generally they are at their best in light shade such as in the dappled light of eucalypts. A notable exception to the general rule is the coast rosemary, Westringia fruticosa. This has proven to be extremely hardy in a wide range of soils and climates and is particularly tolerant of exposed coastal conditions.

As it is the most commonly grown member of the family, the following general points for cultivating Prostanthera are worth noting:

• Species should be selected that are native to a climate similar to that where they are to be grown. In humid, summer-rainfall areas, avoid species from drier climates.
• Mint bushes are usually quick growing and are ideal for providing a quick, colourful effect in a new garden. However, they may be past their best after 6-8 years.
• Mint bushes should be pruned back by about one third after flowering to maintain a bushy habit.
• Mint bushes often wilt noticeably when moisture is lacking in a garden. They are excellent "indicator" plants because of this.
• They are not demanding as far as fertilizing is concerned but they do respond to applications of slow release fertilizer applied after flowering.

The following table lists some of the more readily available members of the mint bush family and their characteristics.