Ailanthus altissima (Miller) Swingle

Synonyms - Ailanthus glandulosa, Toxicodendron altissimum.

Family: - Simaroubaceae


Ailanthus is derived from ailanto meaning "sky tree".

Altissima is Latin for tall.

Tree-of-Heaven refers to its height in reaching for the heavens.

Other Names:


Copal Tree

Varnish Tree


An invasive, deciduous, ornamental shrub or tree usually 3-4 metres or up to 30 metres tall with a broad spreading crown with few branches. It forms suckers freely. The leaves are sticky and 30-100 cm long with 12-30 paired and opposite leaflets that emit an odour from 1-4 small round glands on the underside when crushed. Clusters of greenish to pink flowers form on the ends of branches in November and produce a flattened seed with papery wings that persists on the plant for some time.




First leaves:


Alternate, sticky and foul smelling when crushed, 200-1000 mm long and composed of 10-20 opposite leaflets and a single terminal leaflet. They are only produced on new wood.

Stipules - tiny or absent.

Petiole - 40-70 mm long. Main axis of leaf is often red. Leaflets have a short 2-10 mm long and often red petiolule.

Blade - Of leaflet, egg shaped, 40-130 mm long by 25-50 mm wide with 1-4 teeth near the base that have 1 or more, small, round oil glands at their tip and on the under surface that emit an unpleasant odour when crushed. The tip is pointed and the base rounded and asymmetrical.


Single stem up to 30 m tall with a few spreading branches, but often there are thickets of stems that arise individually from the lateral roots.

Bark - Grey to yellow-grey, slightly roughened and pitted lower on older wood. On leaf bearing young wood it is relatively smooth, pitted, reddish and speckled.

Sapwood is ring porous.

Flower head:

Clusters of flowers up to 60-600 mm long at the ends of branches.


Greenish to pinkish or white, small and about 6 mm diameter. Male and female flowers are on separate plants. Male flowers emit a foul smell that attracts insects.

Female flowers form several fruits.

Ovary - free

Styles - fused

Calyx - Lobes 1 mm long.

Petals - 5, white, narrow, oblong, 3-4 mm long, woolly at the base.

Stamens - 10, dimorphic, 2.5 mm long in male flowers.

Anthers -




Flattened, disk-shaped, 3 mm diameter, yellow to green and becoming red with age. Surrounded by a large (40 mm long by 10-15 mm wide), smooth, papery wing. No endosperm.


Deep taproot and many shallow laterals that sucker freely forming dense clumps of stems.

Key Characters:

Deciduous tree.

Leave alternate.

Leaflets > 22 mm wide, lobed near the base, lobes glandular at the apex.

Flowers unisexual.

Petals woolly at the base.

Adapted from Gwen Harden, Flora of NSW.


Life cycle:

Perennial. Germinates from seed in spring and young plants form an extensive root system in their first year. The first flowering occurs when the plants are more than 2 years old. The leaves fall in autumn and new leaves appear on new growth in spring. It flowers in summer and seed are produced from late summer to autumn. It forms suckers from roots and may produce dense thickets. This is the main method of local spread. Dumped cuttings readily form roots and produce new trees that flower in the following summer to autumn. Few plants seem to establish from seed.


It can survive in harsh urban environments such as in cracks in concrete and in shallow pockets of soil.


Pollinated by insects.

Large amounts of seed are produced but few plants appear to establish from seed. Most spread is by intentional planting, suckering and dumping of cuttings.

Flowering times:

Late summer to autumn in western NSW.

Seed Biology and Germination:

Large quantities of seed produced but poor establishment. Germinates in spring.

Vegetative Propagules:

Suckers from roots. Root and stem fragments.



The leaves produce chemicals which inhibit the growth of companion plants and this often results in single species stands.

Population Dynamics and Dispersal:

Spreads by suckering and seeds. The wing on the seed assists spread by wind and water. It is spread also by birds, machinery and in produce. Cultivation and road works spread root fragments and lopping spreads cuttings which may establish where they are deposited.

Origin and History:

Eastern China, eastern Asia.

Introduced as an ornamental. It was in NSW by 1845 and Victoria and South Australia by the 1850's

Introduced into the USA in 1784.





Humid and sub humid warm temperate areas.


Wide range from clays to sands. Prefers clay to loam soils in moderate rainfall areas.

Plant Associations:



Ornamental, shade tree around stock yards, firewood, paper pulp.

The wood heavy and strong and is good for furniture, cooking utensils and musical instruments because it doesn't warp or shrink.

Use in herbal medicine. Food for shantung silk worms.

Honey has an unpleasant taste initially but this disappears after a few months.


Weed of disturbed and semi natural bushland, degraded pastures, streams and gardens.

Invasive weed that forms clumps and thickets by abundant suckers and seedlings displacing native vegetation.

Blocks sewers and disturbs building foundations.

Invasive weed of the USA.

Grows from dumped cuttings.


The bark and leaves are suspected of poisoning stock.

May cause contact dermatitis in humans, especially when in flower. Flowers falling in drinking water may cause dermatitis and gastritis.


Skin rash.



Noxious weed of Victoria, Western Australia and New South Wales.

Management and Control:

After cutting the main stem it forms abundant sprouts and suckers. Repeated removal of these will eventually kill the tree but this is difficult and may take some time. A combination of mechanical removal and herbicides is usually required.

Neat glyphosate or diluted picloram and triclopyr as a basal bark or overall spray on small trees or application to the stump as soon as it is cut on larger trees is usually effective.

Metsulfuron as a foliage spray is effective. Hexazinone as a spot gun treatment for individual plants or as grid ball treatments for infestations is also effective.

Cultivation is rarely effective and 2,4-D is rather variable in its control.


Eradication strategies:

Cut large trees close to the ground then apply neat glyphosate or 1:60 Access in diesel immediately to the cut stump.

Paint the lower metre of bark of smaller trees and suckers with neat glyphosate


Spray overall and a 5 m buffer around the infestation with 1 litre of Grazon plus 250 mL Pulse in 100 L of water in early summer.

Respray regrowth annually.

Herbicide resistance:

None recorded.

Biological Control:

Related plants:

Plants of similar appearance:


Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P223. Photo.

Bodkin, F. (1986). Encyclopaedia Botanica. (Angus and Robertson, Australia).

Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne). P450. Photo.

Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney).

Harden, Gwen J. (1991). Flora of NSW. (Royal Botanic Gardens, Sydney). Volume 2. P276. Diagram.

Hussey, B.M.J., Keighery, G.J., Cousens, R.D., Dodd, J. and Lloyd, S.G. (1997). Western Weeds. A guide to the weeds of Western Australia. (Plant Protection Society of Western Australia, Perth, Western Australia). P218. Photo.

Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).

Lazarides, M. and Cowley, K. and Hohnen, P. (1997). CSIRO handbook of Australian Weeds. (CSIRO, Melbourne). 31.1.

Parsons, W.T. and Cuthbertson, E.G. (1992) Noxious weeds of Australia. (Inkata Press, Melbourne). P589-591. Photos.

Randall, J.M. and Marinelli, J. (1996) Invasive Plants. (Brooklyn Botanic Gardens Inc. Brooklyn). P27. Photo.


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