Hardenbergia is a small genus of three species, the most common and best known of which is Hardenbergia violacea.
Hardenbergia comptoniana is a vigorous climbing plant whose branches twist around the stems of other plants. The leaves are usually tri-foliate with dark, glossy green leaflets ranging from broadly linear to ovate. Leaflets are up to 150 mm long by 10-60 mm wide. The flowers, which appear in winter and spring, are usually mauve to purple in colour but pink and white forms are known.
The flowers are the typical “pea” shape consisting of 4 petals; the “standard”, the “keel” and two “wings” as shown in the accompanying diagram.
H.comptoniana has been in cultivation for many years and is widely grown both in Australia and overseas. It has proven to be very hardy in a wide range of climates and most reasonably drained soils. It will grow in sunny or lightly shaded locations. It is usually more vigorous than H.violacea and should not be allowed to grow over smaller shrubs. It grows well on a strong support such as a fence or trellis.
Propagation is easy from seed following pre-treatment to break the physical dormancy provided by the impervious seed coat. Pre-treatment can be carried out by abrasion or by the use of boiling water (further details can be found in under the “Propagation” tab of the “Pea Family” page). The seed retains viability for many years. Cuttings strike well using firm, current season’s growth.
Photo: Garin Dadson