Soap-Bark Tree, Soapbark
Quillaja saponaria
Family: Quillajaceae
What it is like
Quillaja saponaria is an evergreen Tree growing to 18 m (59ft) by 6 m (19ft) at a slow rate. See above for USDA hardiness. It is hardy to UK zone 10 and is frost tender. It is in leaf all year, in flower from April to May. The species is hermaphrodite (has both male and female organs) and is pollinated by Insects. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It cannot grow in the shade. It prefers moist soil.
Height (m): 18
Where it is found
Mountainous regions on the western slopes of the Andes.
S. America - Chile, Peru.
Conservation Status:
Countries/locations it is found in
How it is used
Food
Rating: 0
Medicine
Rating: 3
Soap bark tree has a long history of medicinal use with the Andean people who used it especially as a treatment for various chest problems. The saponin content of the bark helps to stimulate the production of a more fluid mucous in the airways, thus facilitating the removal of phlegm through coughing. The tree is useful for treating any condition featuring congested catarrh within the chest, but it should not be used for dry irritable coughs. The inner bark contains about 9% of complex saponins, known collectively as 'quillajasaponin'. It also contains calcium oxalate and tannin. It has been used internally as a stimulating expectorant, though it can cause irritation and inflammation of the digestive tract and so is no longer considered safe. The internal use of this plant needs to be carefully overseen by a professional practitioner. Sap bark tree is used as a source of compounds for the pharmaceutical industry. It is still used externally as a cutaneous stimulant in the treatment of skin ulcers and eruptions, dandruff etc.
Antiseborrheic: Used in the treatment of seborrhoeic dermatitis.
Expectorant: Clears phlegm from the chest by inducing coughing.
Skin: Plants used in miscellaneous treatments for the skin.
Stimulant: Excites or quickens activity of the physiological processes. Faster acting than a tonic but differing from a narcotic in that it does not give a false sense of well-being.
Other
Rating: 0
The fresh or dried inner bark is a soap substitute. It contains about 9% saponins and is a very gentle and effective cleaner. It is used for cleaning textiles and the skin. It can also be used as a hair tonic. The saponins are also used in anti-dandruff shampoos and exfoliant cleansers. They are used as a foaming agent in fire extinguishers. The bark also contains considerable quantities of carbonate of lime.
Hair: Plants used as hair shampoos, tonics, to treat balding etc.
Soap: Plants used directly as a soap substitute.
How it is grown
Requires a well-drained fertile soil in a sunny position. Plants are hardy to about -12°c in their natural range in South America but they usually require greenhouse protection in Britain. They can succeed outdoors in the milder areas of this country, often as small shrubs but making a tree in the very mildest areas. The young growth in spring can be damaged by late frosts, so it is best to site the plant in a position sheltered from the early morning sun. This species is cultivated for the saponins in its bark in some warm temperate areas of the world.
Propagating it: Seed - sow spring in a greenhouse. Prick out the seedlings into individual pots when they are large enough to handle and 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. Cuttings of fully ripe wood of the current year's growth, November in a frame.
Best place to grow: Woodland Garden Secondary; Sunny Edge; South Wall. By. West Wall. By.
Habit: Tree
Hardiness: 9-11
Growth: Slow
Soil: Light (sandy), medium, heavy (clay)
Shade: No shade
Moisture: Moist
Things to keep in mind
The plant is toxic if taken internally, tending to dissolve the blood corpuscles. The bark, and possibly other parts of the plant, contains saponins. Although toxic, saponins are very poorly absorbed by the body and so tend to pass through without causing harm, they are also destroyed by thorough cooking. Saponins are found in many plants, including several that are often used for food, such as certain beans. It is advisable not to eat large quantities of food that contain saponins. Saponins are much more toxic to some creatures, such as fish, and hunting tribes have traditionally put large quantities of them in streams, lakes etc in order to stupefy or kill the fish.