• Home
  • |
  • Blog
  • |
  • Quillaja Saponaria: Soapbark Tree

Quillaja Saponaria: Soapbark Tree

Quillaja saponaria, commonly known as the Soap-Bark Tree or simply Soapbark, grows to a height of 18m and a width of 6m. With a slow growth rate, this tree boasts a hardness rating of 10, showcasing its resilience to frost.

The Soapbark Tree flowers from April to May, producing hermaphrodite flowers (having both male and female organs) that are pollinated by insects.







18 metres


6 metres


S. America - Chile, Peru.

Soil Information for Quillaja saponaria:

  • The tree thrives in various soil types, including light (sandy), medium (loamy), and hard (clay) soils.
  • Well-drained soil is crucial for its growth.
  • Preferred soil pH levels:
    • Less than 6 for acidic soils.
    • Between 6 and 8 for neutral soils.
    • Greater than 8 for basic soils.
  • The Soapbark Tree has a preference for moist soils.

Ideal Planting Locations for Soapbark Tree:

  • It's best to avoid planting the Quillaja saponaria in shady areas.
  • Naturally found in mountainous regions on the western slopes of the Andes.
  • Suitable planting locations include:
    • Woodland gardens.
    • As a secondary tree.
    • Sunny edges.

Cultivation Details of Quillaja saponaria

The tree requires a well-drained fertile soil in a sunny position. While it's hardy to about -12°C in its native South American range, it often requires greenhouse protection in colder regions.

However, in milder areas, it can flourish outdoors, sometimes as a shrub or even as a tree in the warmest locales.

The young growth in spring can be susceptible to late frosts, so it's advisable to plant in a location sheltered from the early morning sun. This species is cultivated in some warm temperate areas for the saponins in its bark.

Propagation of Quillaja saponaria


  • Sow in spring in a greenhouse.
  • Prick out the seedlings into individual pots when they are large enough to handle.
  • Grow them on in the greenhouse for at least their first winter.
  • Plant out in early summer and give some protection from the cold for at least their first winter outdoors.


  • Use fully ripe wood of the current year's growth.
  • Take cuttings in May to June (late autumn to early winter in Australia) and place them in a frame.

Medicinal Uses of Soapbark

Soapbark tree has a rich medicinal history, especially among the Andean people. It's been traditionally used for various chest problems.

The saponin content in the bark aids in producing a more fluid mucus in the airways, facilitating phlegm removal. 

However, it's not recommended for dry, irritable coughs. The inner bark contains about 9% of complex saponins, calcium oxalate, and tannin.

While it's been used internally as a stimulating expectorant, it can irritate the digestive tract. Hence, its internal use should be overseen by a professional.

Other Uses of Soapbark Tree

  • Natural Soap Substitute: The inner bark, fresh or dried, is an effective soap alternative, suitable for washing textiles and skin.
  • Hair Care: The tree's saponins are used in hair tonics and anti-dandruff shampoos.
  • Exfoliation: The saponins are ingredients in exfoliant cleansers.
  • Industrial Uses: The saponins are used as foaming agents in fire extinguishers.
  • Additional Components: The bark contains significant amounts of carbonate of lime.


The New RHS Dictionary of Gardening. 1992.

  • Huxley. A.
  • Author: Huxley. A.
  • Rating:
  • Publisher : Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
  • Date of Publication: 1992

Wrapping up the Soapbark Tree Guide

The Quillaja saponaria, or Soapbark Tree, is a versatile and resilient tree with numerous applications, from medicinal to industrial. Its unique properties make it a valuable addition to Australian gardens, offering both aesthetic appeal and practical benefits.

Whether you're interested in natural remedies, sustainable cleaning solutions, or simply a beautiful tree for your garden, the Soapbark Tree is a worthy consideration.

Related Posts

Kurrajong Tree (Brachychiton populneus) Growing Guide

Kurrajong Tree (Brachychiton populneus) Growing Guide

The Kurrajong tree being native to Australia, is often seen ...

How to Grow and Care for Christmas Tree

How to Grow a Christmas Tree in Australia

Christmas wouldn't be Christmas without a decorated tree covered in ...

Magnolia x soulangeana: Australian Growing Guide

Magnolia x soulangeana: Australian Growing Guide

Thanks to its reliable late-winter flowering, and spectacular blooms, the ...

Miracle Berry: Synsepalum Dulcificum Growing Guide

Miracle Berry: Synsepalum Dulcificum Growing Guide

The first seeds of miracle fruit arrived in Australia in ...


Nathan Schwartz

Leave a Reply

Your email address will not be published. Required fields are marked

{"email":"Email address invalid","url":"Website address invalid","required":"Required field missing"}

Stay Up To Date With Aussie Gardening Tips

Join our newsletter to receive helpful gardening tips specific to Australian gardens.


  • Seasonal gardening tips
  • Monthly gardening tasks for each Australian climate
  • Native plant of the month
  • A curated selection of helpful gardening articles
  • Exclusive promotions for Australian gardeners

Stay in the loop for valuable insights for a flourishing garden.

We promise to only send you helpful gardening emails and nothing more.