Alphitonia excelsa

red ash


Alphitonia excelsa

(Fenzl) Reissek ex Benth. 1863

pronounced: al-fit-OH-nee-up ek-KEL-suh

(Rhamnaceae — the buckthorn family)


common names: red ash, soap tree

native 4Alphitonia is derived from the Greek αλφιτον (alphiton), barley meal, and refers to the dry, mealy quality of the mesocarp in the fruits; excelsa is from the Latin excelsus, elevated, high.

The Red Ash grows in eucalypt forests, eucalypt and acacia savannas, gallery forests and rainforests of NSW from Mt Dromedary northwards along the coast through Queensland and the Northern Territory, into the northwest of Western Australia. It is also found in New Guinea and on some of the Pacific Islands. It is a small to medium tree, up to about 20 m tall, is a natural colonizer or pioneer in a huge range of conditions, and can sometimes regenerate from underground stems. It has a spreading, shade-producing habit where it is able to grow into a large tree, and has an overall greyish green appearance.

The trunk and larger branches have fissured grey bark, with smaller branches having smoother grey or white bark. Lichens are often found on older specimens.

The entire, simple, alternate leaves are 5 – 14 cm in length and 2 – 5 cm in width, elliptic in shape, and are dark glossy green above and silvery with fine hairs underneath, making an attractive contrast on windy days. Venation is prominent and yellowish below, and sunken above. In the dry season, many of the leaves are shed, and the remaining leaves hang vertically to reduce water loss.

The tree bears small greenish white 5-petalled flowers in late autumn and early winter, followed by globular dark fruit about 1.5 cm in diameter, with a raised ring around the middle. The powdery red flesh of the drupe covers 2 hard cells, each containing a single seed. Seeds can persist on the branches for several months. When young shoots are bruised, they give off a typical odour of sarsaparilla. The flowers are fragrant in the evening.

When grown under cultivation, this is quite a quick-growing tree, and can have high visual appeal, especially as a street tree. Its tough timber is light brown to reddish in colour, and has been used in boat building and cabinet-making, particularly in Samoa, where the tree is known as toi.

The leaves are eaten by many insects, often giving the tree a ragged appearance. These insects do attract quite a number of bird species, especially cockatoos. It is a food plant for many lepidoptera caterpillars, including those of:

       • the Moonlight Jewel butterfly Hypochrysops delicia,
       • the Emperor Moth Opodiphthera astrophela,
       • the Clearwing Persimmon Borer Ichneumenoptera chrysophanes,
       • the Large Green-banded Blue Danis danis,
       • the Small Green-banded Blue Psychonotis caelius,
       • the Pomaderris Moth Casbia rectaria,
       • the moth Phyllocnistis atranota, and
       • the Copper Jewel Hypochrysops apelles.

Aborigines used the crushed leaves and berries as a fish poison. For medical use, they crushed the leaves into a paste, mixed that with water and applied it as a head bath to reduce headaches and treat sore eyes. Infusions of the bark and root were rubbed on the body to reduce muscular ache, and gargled to cure toothache. The leaves contain saponin, and so when crushed can be lathered to produce a bush soap. In Borneo, the sap from under the bark is collected, and used to treat skin diseases by mixing it in the bath water.


Information about medicinal qualities of plants, or about their use as medicines, is for interest only, and is not intended to be used as a guide for the treatment of medical conditions.

Photographs taken at Nelly Bay 2010-2016
Page last updated 4th October 2018