ADVERTISEMENT

ADVERTISEMENT

10 Trees that are Classified as Weeds in Australia

Generally, these species spread readily into bushland areas and crowd out many of our native species.

There are numerous tree species from around the world that are classified as weeds in Australia.

Generally, these species spread readily into bushland areas and crowd out many of our native species.

Here’s a rundown of the most prominent tree species that are regarded as environmental weeds in Australia.

Black Cutch (Senegalia catechu)

Black Cutch Senegalia catechu | Weed control
Senegalia catechu / Photo by Dinesh Valke / Flickr / CC BY-SA 2.0

There are known stands of the Black cutch that are currently being removed in Darwin. This small tree has the capacity to form dense impenetrable stands across pasture lands.

Plus, the sharp thorns found on the base of each leaf mean that these trees can also interfere with the movement of stock.

Black Locust (Robinia pseudoacacia)

Black Locust Robinia pseudoacacia | Weed control
Robinia pseudoacacia

Most people would be familiar with the black locust that is native to the United States. This is a deciduous tree that has suckering roots. This means that it can spread easily and quite quickly.

Primarily, this tree has become a problem in a variety of different states across the country including Tasmania, Victoria, NSW, South Australia, WA and Queensland.

It’s also important to note that all parts of the tree are toxic to humans and animals including stock.

The leaves are divided and have 5 to 10 pairs of leaflets on each leaf stem. The flowers can be white, purple or pink and grow on large pendulous racemes.

Box Elder (Acer negundo)

Box Elder Acer negundo | Weed control
Acer negundo

This deciduous maple has been widely cultivated as a garden ornamental and also as a specimen in parks and as a street tree.

The winged seeds are easily dispersed by the wind and this tree has become an invasive weed in moist forest areas and along riverbanks.

Broad-leaved Cotoneaster (Cotoneaster glaucophyllus franch.)

Cotoneaster glaucophyllus | Weed control
Cotoneaster glaucophyllus / Photo by John Tann / Flickr / CC BY 2.0

This small tree is a familiar sight in many older gardens. It originally came from China and can easily be identified by its bright red berries in autumn.

These berries are loved by birds and that’s how the seeds have been spread into bushland areas.

Broad-leaved Privet (Ligustrum lucidum)

Broad leaved Privet Ligustrum lucidum | Weed control
Ligustrum lucidum

This tree is native to eastern Asia and has escaped gardens to invade natural bushland as the seeds are spread by birds. It’s become a particular problem in rainforests and gullies of coastal areas in eastern Australia.

It’s a dense tree that has the capacity to shade out native tree species and destroy the natural habitat of many of our native animals.

The tree has large, semi-glossy leaves that are quite thick and leathery. The flowers are cream or white and appear on large branched clusters, usually at the tips of the stems. 

Broad leaved Privet Ligustrum lucidum 1 | Weed control
Ligustrum lucidum

The fruits are berry-sized and purple to black when mature. 

The Chinese privet (Ligustrum sinense) is also classified as a weed species in Australia.

Chinese Apple (Ziziphus mauritiana)

Chinese Apple Ziziphus mauritiana | Weed control
Ziziphus mauritiana

The Chinese apple is a small tree that is native to Asia, eastern Africa and islands in the Indian Ocean. It has become a weed species in both tropical and sub-tropical regions of Australia.

Each tree can produce around 8,000 to 10,000 seeds per year which means that the tree can spread rapidly and have a problematic impact on our native species.

This tree produces rounded leaves and crisscrossing stems that have thorns on the ends. The flowers are relatively small and insignificant but have an unpleasant scent.

The tree also produces small pale yellow or orange fruits that are edible.

Prickly Acacia (Vachellia nilotica)

Prickly Acacia Vachella nilotica | Weed control
Vachellia nilotica

This small tree species hails from India and is now widespread in Queensland. It can form dense, thorny thickets in pasture land. This interferes with stock movement.

The leaves on this tree are fern-like and the flowers are golden yellow and ball-shaped. The tree also has paired thorns that are around one to five cm long. 

Rhus Tree (Toxicodendron succedaneum)

Rhus Tree Toxicodendron succedaneum 1 | Weed control
Toxicodendron succedaneum

This is a small tree that is native to China and Japan. It has brightly colourful deciduous foliage in autumn. This tree is also highly toxic to humans and should not be burnt.

It has spread into bushland by birds and the sap of the tree can cause severe dermatitis. Therefore, protective clothing must be worn when removing any parts of this tree.

Sweet Pittosporum (Pittosporum undulatum)

Sweet Pittosporum Pittosporum undulatum | Weed control
Pittosporum undulatum / Photo by Krzysztof Ziarnek / Wikimedia / CC BY-SA 4.0

Although sweet pittosporum is native to Australia, it has spread outside of its natural habitat because it’s become a popular garden plant and street tree. 

The problem that this species has caused is that it shades out other native species and alters the nutrient levels in the soil.

The tree produces a dense canopy with leaves that are oval, deep green and arranged alternately on stems.

The tree also produces white flowers and obovate fruit capsules that contain orange seeds.

Tipu Tree (Tipuana tipu)

Tipu Tree Tipuana tipu | Weed control
Tipuana tipu

This attractive shade tree has become a problem in Queensland and NSW because it can seed readily and spread into natural bushland areas. It has been commonly grown as an ornamental or shade tree.

The tipu or Rosewood tree can reach a height of 10 metres and forms a dense canopy with deep green oval-shaped leaves. The tree also produces bright yellow flowers and distinctive winged fruit.

The winged seeds can be spread long distances by wind.

More weed trees can be found on the Weeds Australia website.

FAQ:

What are the woody weeds in Australia?

Woody weeds found in Australia include willows, yellow box, wilgas, yellow bells, blackberry, Paterson’s curse, prickly acacia and thornapple.

Are pine trees weeds in Australia?

Certain species of pine trees are classified as weeds in Australia. These include the Aleppo pine, Athel pine and the radiata pine.

Photo of author

Annette Hird

Annette Hird is a gardening expert with many years of experience in a range of gardening related positions. She has an Associate Diploma of Applied Science in Horticulture and has worked in a variety of production nurseries, primarily as a propagator. She has also been responsible for a large homestead garden that included lawn care, fruit trees, roses and many other ornamental plants. More recently, Annette has concentrated on improving the garden landscape of the homes that she has lived in and focused a lot of energy on growing edible plants as well. She now enjoys sharing her experience and knowledge with others by writing articles about all facets of gardening and growing plants.

ADVERTISEMENT

Leave a Comment