Tree of Heaven

Ailanthus altissima

Family: Simaroubaceae

Type of weed:

Flowering Months: , ,

Description

Tree of Heaven is a fast-growing deciduous tree to 20 m high with smooth, grey bark.

Large compound leaves are up to 1m long with many leaflets in opposite pairs, each with at least one small thumb like tooth near the base.

Flowers are in terminal clusters mostly 6–12 cm long; male and female flowers are on separate plants (dioecious). Male flowers emit an offensive smell that attracts insects. It flowers in summer.

The bark, leaves and flowers of this species are poisonous to humans and livestock and contact is known to cause dermatitis in humans. Drinking water contaminated with flowers has been reported to cause dermatitis and gastritis.

Don’t confuse with…

Tree of Heaven can be confused with Australian Red Cedar (Toona ciliate). The Cedar does not have the thumb like tooth on the leaf base, nor the distinctive smell.

Dispersal

Seed dispersed by wind, birds and animals; it suckers from the roots and can be spread by machinery.

Impact on bushland

Tree of Heaven suckers profusely and therefore forms dense stands of trees that are interconnected. It can out compete native plants for nutrients and light. It inhibits growth of other plants by creating a toxic soil environment.

Distribution

, . Whole of Local Government Area, particularly Blaxland, Glenbrook, Springwood. Also Jenolan Caves and Cumberland Plains.

Alternative planting

Native plants

  • Christmas Bush (Ceratopetalum gummiferum)
  • Native Peach (Trema aspera)
  • Red Bottlebrush (Callistemon citrons)
  • Bleeding Heart (Omolanthus populifolius)

Council provides a tool, on its Mountain Landscapes website, to help you choose native alternative plantings. Choose your village, soil, vegetation community and the purpose of your planting, and the tool will give you suggestions.

There are native nurseries in several Blue Mountains villages, including Glenbrook, Lawson and Katoomba. Please also ask at your favourite local nursery.

Control

Care must be taken when treating Tree of Heaven. Avoid contact with the sap.

Because of its vigorous ability to sucker, plants cannot be treated individually by hand removal or the cut and paint method. Follow up treatment of suckers and regrowth is required for a number of years. Tree of Heaven does not respond well to herbicide.

Every stem must be treated — regardless of size — both in the primary treatment and in follow up.

  • Thin stems should be scraped and painted. Scrape as far as possible along the leangth of each stem and paint.
  • Larger stems should be drilled and injected.
  • Scrape and paint or drill and inject exposed roots.

Refer to the NSW Department of Primary Industry’s Noxious and Environmental Weed Control Handbook.