Hardenbergia | Australian Native Growing Guide

Hardenbergia Plant Details

Hardenbergia is a genus of three species of plants in the pea family, Fabaceae and is endemic to Australia. The evergreen vine Hardenbergia species has dark green, smooth, spear-shaped leaves which grow between 2.5 to 13 centimetres long. The vines climb using tendrils that attach to a support structure.

The Hardenbergia produces a pea-shaped flower and the blooms are four petals. The 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 honour of Franziska Countess von Hardenberg in 1837.

In the wild, Hardenbergia grows through tree branches and across canyons and the plant is hardy to -3 degrees Celsius. This nitrogen-fixing plant is known by Australia’s aborigines as Waraburra.

When growing the plant from seed, pre-treatment is necessary. Hardenbergia seed requires acid scarification and pre-soaking in water at least 24 hours before sowing due to its hard seed coat.

Hardenbergia also needs to germinate in warm temperatures of at least 21 degrees Celsius.

More About Hardenbergia

Hardenbergia is a hardy, evergreen, vigorous climbing plant. From winter through to spring, this plant produces an abundance of dark purple, pale pink or white pea flowers depending on the variety.

The plant needs a sunny or semi shaded position in the garden with free draining soil that contains manure or compost. This plant can also handle light frosts but ideally needs temperatures above 6 degrees Celsius. 

Hardenbergia are fast growing and low maintenance. They can trail over fences if you’re looking for floral coverage and privacy or even trail along a trellis. Plant Hardenbergia as a beautiful feature plant or plant as a mass for a huge blooming impact.

You’ll need to water moderately all year round except in summer and prune the plant to 2/3 its size in late winter. The good news is this plant are quite resistant plants to pests and diseases and they propagate in late summer by cuttings and by seeds sown in spring.

Growing Hardenbergia in Australia

Growing this plant can be overwhelming if you don’t keep it in check. They can reach 15 metres in length, and the plant will twine itself around and climb everything in its path.

This means you’ll need to choose your planting site carefully and make sure the plant has a large, strong structure to climb or plenty of ground to spread. 

Watering Schedule 

Water throughout the active growth period, when the soil is dry to the touch and during periods of drought. You can apply a balanced liquid fertiliser monthly for better flowering and foliage. Keep the plant just moist in winter. 

Sunlight Needs

Hardenbergia will be happiest in an area with full sun or part shade. They will thrive in full sun in areas with temperate summers. If your summers are very hot, plant in a place that gets some afternoon shade.

Best Soil to Use

This plant are best planted in well-drained soil of loam and sand with a neutral or acidic pH balance. If planting outside, you can tweak the native soil with organic matter to improve drainage.

If you are planting Hardenbergia in pots, you’ll need a loam-based potting compost with plenty of sharp sand and leaf mould. After planting, you want to water thoroughly and deeply to help the soil settle.

Pruning Hardenbergia 

You can do some pruning at any time of year to keep your Hardenbergia in check. If you’re doing severe pruning, to half or even a third of its size, do this in spring after flowering is finished.

Hardenbergia Propagation

The easiest way to propagating Hardenbergia is by taking softwood cuttings during spring. To propagate successfully, you should take a cutting from the flexible young shoot tips.

Pinch out the soft tip and dip it in a hormone rooting powder or liquid. Make sure you have a container with cutting compost ready. 

Make a hole for your cutting and insert into your container. Water thoroughly. Place the container with your cutting somewhere with a steady temperature ranging from 18-24°C.

These cuttings should be kept in a humid environment, so you can cover them in a plastic bag, making sure to remove the bag twice a week for about 15 minutes. It is vital that your cuttings are kept in partial sunlight with soil that is moist, for 6-10 weeks. 

Once you are happy that your cuttings have rooted successfully, you can pot them individually. Increase their ventilation and remove dead or rotting foliage on a regular basis.

Hardenbergia Bush Tucker Guide

Although the flowers of this plant are not edible, you can add them to tea as a sweetener. You can also brew tea from the leaves, then cool and sweeten with native honey.

The tea is similar to green tea in flavour. You can crush and boil the leaves to achieve the desired flavour. 

Our Australian bush tucker articles are about embracing bush tucker in your everyday life. We focus specifically on the flora aspect of native Australian food and medicine. 

Hardenbergia Pests and Diseases to Look Out For

Hardenbergia are susceptible to powdery mildew in cool moist weather. If this happens, the plant should be monitored and treated with an appropriate organic fungicide if needed.

Neem oil is great for this. Neem oil works by preventing the germination and penetration of fungal spores into leaf tissue. Neem oil won't cure a plant that is already infected with a fungal disease, but it can help limit the spread of the disease to healthy tissue.

Fungal problems can be minimised if you avoid wetting the leaves when you do your watering and by removing dead leaves to improve air circulation. 

See our compilation of common lawn problems and their solutions to help you maintain your garden. 

Monitoring your plants for signs of leaf damage helps to avoid major pest infestations, like caterpillars. Scale insects and mealybugs can also become a problem if the plant is too crowded. 

Scale can be a pest for this plant. You can squash or scrape off scale on the stems or the underside of leaves and you’ll need to heavily prune infested growth. If you’re dealing with serious infestations, you can spray with neem oil.

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Hardenbergia Frequently Asked Questions

What were the historical uses of the Hardenbergia plant?

Indigenous Australians used the flowers of the Hardenbergia as a seasonal calendar of sorts. It helped them decide when they could fish from the creeks sustainably. They also used the plant for:

• Treating mouth ulcers, chest complaints, and stomach cramps
• Eating flowers to detox and cleanse
• Weaving the vine to create ropes, fishnets and traps
• Making a dye from the flowers

What is the nutritional value of the Hardenbergia seeds?

Hardenbergia seeds are high in Potassium, Calcium, Manganese, Magnesium, Zinc, Copper, Nitrogen and Sodium.

Why is Hardenbergia sometimes called a soil medicine?

The plant actually fixes nitrogen in soils for use by other plants.

What kind of dye do you get from Hardenbergia flowers?

A grey-blue dye is obtained from the flowers.

Looking for more purple plants to grow in your garden? If you are, then be sure to check out our comprehensive guide to growing Hovea acutifolia, also known as the purple pea bush.