Hardenbergia is a genus made up of three species of Australian leguminous vines. H. comptoniana, H. perbrevidens, and H. violacea are the species. Belonging to the family Fabaceae, which includes all legumes, these species can be grown as ground cover or as a climbing plant.
In the wild, Hardenbergia grows through tree branches and across canyons. In Australia it is known by the common names native sarsaparilla and vine lilac. The plant is hardy to 24 degrees Fahrenheit (-3 degrees Celsius).
An evergreen vine, the Hardenbergia species have dark green, smooth, spear-shaped leaves. The leaves grow from 1 to 5 inches (2.5 to 13 cm) long. The vines climb using tendrils that attach to their support.
H. violacea is the species most commonly cultivated, with the other two being found primarily in the wild. Also known as a purple coral pea, the plants can grow up to 10 feet (3 m) tall and 5 feet (1.5 m) wide. The Hardenbergia blooms in colors of violet, pink, and white from mid-winter to mid-spring in large clusters of small flowers.
With copious, showy flowers, the presence of Hardenbergia in a garden often attracts birds before other flowers start to bloom. A pea-shaped flower, the blooms are four petals. Common cultivars found in nurseries include the happy wanderer in purple, the pink fizz, and the purple falls. The name of the genus is from English botanist George Bentham, who titled the three species in honor of Franziska Countess von Hardenberg in 1837.
A nitrogen-fixing plant, it is known by Australia’s aborigines as Waraburra. The flowers of the plants are eaten and used to make dye and tea. The seeds provide food for wildlife. In gardens it is often planted along fencerows as ground cover or border, trellised or placed in hanging baskets. It is tolerant of high winds and first-line salt winds.
When cultivating, the plants should be grown in full sun to light shade. It does best in soil that drains well and needs regular watering. Once it is well established, it is somewhat drought tolerant. Propagation is by tip cuttings in the spring and hardwood cuttings in later summer. It is also cultivated by seed.
When growing from seed, pre-treatment is necessary. This is most often done by scaring the seed or boiling the seed in water before it is planted. The seeds are collected from the pods of the Hardenbergia, as they are with other legumes.