Botanic Gardens Trust, Sydney, Australia

Growing Hardenbergia violacea Flat White™ and Carpet Royale™

General planting and care

Hardenbergia violacea Flat White™ and Carpet Royale™ are fast growing, heavy flowering, shallow rooted plants with long trailing stems forming a dense mat, and unlike most other varieties of Hardenbergia will not climb allowing them to be used in a variety of positions in the garden.

They have large glossy leaves and are available in two different flower colours, white and mauve. Once established, they have low water and maintenance requirements.


A full sun to part shade position is preferred in a wide range of soil types including light clay or sand however these cultivars will grow best in an enriched well drained acid soil on a raised bed with a pH of 5.5 to 6.0.

They possess a low frost tolerance when young and can sustain significant leaf damage but will become hardier with age.


It is not recommended that you transplant Hardenbergia violacea Flat White™ or Carpet Royale™ once established.


Avoid wetting the foliage to minimise possible fungal problems. Monitor watering levels in the first season after planting and during the warmer months of the year to maintain adequate soil moisture. Once established and in the cooler months of the year these cultivars require minimal watering.


Fertilise with a general purpose 3 to 4 month slow release fertiliser in spring and autumn. Supplementary applications of a complete liquid fertiliser at 2-3 weekly intervals will assist with plant health and vigour.

A liquid feed of magnesium sulphate (Epsom salts) and iron chelates in April will also assist in maintaining strong vigour prior to flowering especially in sandy soils.


After planting your Hardenbergia it is recommended you mulch to a depth of 5 cm to conserve soil moisture and to assist with plant health.


Heavy pruning, up to two thirds of the plant, after flowering is advised to increase vigour and create a bushier plant with increased flowering in the following season.

Pests and diseases

Hardenbergia violacea Flat White™ and Carpet Royale™ are susceptible to Powdery Mildew during cool moist weather and should be monitored and treated with an appropriate organic fungicide if necessary. Fungal problems can be minimised by avoiding foliage wetting during irrigation and by periodically removing dead leaves to improve air circulation. They can also be affected by leaf chewing caterpillars. Monitoring plants for evidence of leaf damage should be carried out to avoid major pest infestations. Scale insects and mealy bug can also become a problem in crowded situations.

The Hardenbergia violacea Flat White™ and Carpet Royale™ are available for purchase from most good garden centres.



Hardenbergia violacea

Flat White

Carpet Royale

Hardenbergia trial beds