Quick Facts

Quick facts

• Known infestations of Black Cutch (Senegalia catechu) in Darwin are currently under active management, with eradication as the target.
• Preventing its spread and further introduction will protect the savannas and grasslands of tropical Australia.
• Small infestations of Black Cutch can be effectively eradicated if follow-up control is conducted.
• Contact your state or territory weed management agency or local council if you find Cutch Tree. Do not attempt control on your own.

What Does It Look Like?

What is it?

Black Cutch (Senegalia catechu) [as Acacia catechu] is a small tree, growing 3-15 m high with a taproot branching to 2 m depth. The stem is dark brown to black, with rough bark which peels off in long strips in mature trees; young trees have corky bark. The compound leaves are 100-200 mm long and comprise 8 – 30 pairs of primary leaflets each made up of numerous, oblong pairs of secondary leaflets 2-6 mm long. Glands occur on the stem below the first pair of leaves, and between the uppermost six pairs of leaflets. Pairs of stout thorns up to 10 mm long are found at the base of each leaf.

The flowers are white or pale yellow, in a cylindrical flower spike 35-75 mm long.

The seed pods are 50-125 mm long and contain between four and seven seeds, which are dark brown, flat and 5-8 mm in diameter (CRC 2003).

For further information and assistance with identification of Black Cutch contact the herbarium in your state or territory.

Flower colour

White or Yellow

Growth form (weed type/habit)

Tree

Where it currently grows? Preferred habitat

Black Cutch Tree subtropical or tropical open woodlands and grasslands. It grows well on most soils, but well-drained, shallow to medium-depth sandy soils suit it best. In its native range Black Cutch has the tendency to invade degraded areas, e.g. overgrazed grasslands. Regular burning is also conducive to its spread (CRC 2003).

Are there similar species?

There are several native species with similar compound leaves, but all have globular flowerheads. There are three other species of noxious weed that can sometimes be confused with Black Cutch, but all have distinctive differences. Prickly Acacia (Vachellia nilotica) [as Acacia nilotica] has yellow globular flowerheads, and each leaf is divided into only three to six pairs of finely divided leaflets. Giant Sensitive Plant (Mimosa pigra) has pink globular flowerheads and the leaflets close when touched. Mesquite (Prosopis pallida) [as Prosopis limensis] has only one to three pairs of finely divided leaflets per leaf (Flanagan 1998).

Why Is It A Weed?

What are its impacts?

Black Cutch is on the Alert List for Environmental Weeds, a list of 28 non-native plants that threaten biodiversity and cause other environmental damage. Although only in the early stages of establishment, these weeds have the potential to seriously degrade Australia's ecosystems (CRC 2003).

Agriculture: Black Cutch causes economic damage by forming dense impenetrable stands. It can potentially reduce primary production by displacing and/or shading pastures. The sharp thorns on Black Cutch branches can impede the movement and mustering of stock (CRC 2003).

How does it spread?

Black Cutch reproduces by seed. Mature trees produce large numbers of seeds, which can be transported from the parent tree by cattle. The seeds remain viable even after passing through the digestive tract, and can be spread large distances in this way. Seeds can also be spread by the actions of water and people, or in mud sticking to animals or machinery. Although the exact length of time of seed viability is not known, based on related woody weed species it is likely that some seeds remain viable for about 20 years in suitable conditions. Black Cutch will also resprout from the base if the main stem is removed and the cut stump is not treated with herbicide. The regrowth is frequently very dense and composed of numerous stems (CRC 2003).

What is its history in Australia?

In the 1887 Government Resident's Report, Black Cutch was included in a list of useful plants grown in the Darwin Botanic Gardens. In the early 1980s concern was expressed about its weed potential in the Northern Territory. It is not known how Black Cutch escaped the Darwin Botanic Gardens to reach Darwin High School at Bullocky Point, about half a kilometre away, although transport by people, animals or machinery appears likely. Black Cutch has the potential to be a very serious woody weed of the tropical savannas and grasslands of Australia. The Bullocky Point infestation has been eradicated but the plant persists in the Darwin Botanic Gardens (Flanagan 1998; CRC 2003).

How To Manage It?

Best practice management

Any control of Black Cutch should be undertaken cooperatively with your local state or territory weed management agency or local council.

Chemical control: Mature Black Cutch can be killed with herbicide applied by basal bark spraying, stem injection or the cut-stump method. Black Cutch will reshoot readily from a cut stump, so simply removing the stem without herbicide application will not kill it. Note that although herbicides are most effective when plants are actively growing (i.e. the wet season for Black Cutch ); the basal bark technique is least effective when the bark is wet. Once the infestation is initially controlled, follow-up monitoring and treatment should be undertaken at least three times each year. In particular, attention should be paid to re-treating any regrowth from mature trees and removing seedlings that have germinated from the seedbank. Because seeds can remain viable for such a long time, it is important to continue follow-up control for up to 20 years after the last seed drop (CRC 2003).

Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au .

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

Very little is known about the life cycle of Black Cutch in Australia. It mainly flowers in the wet season, but mature trees can flower year round. Seeds ripen and drop at the end of the wet season and throughout the early dry season. Germination occurs after the first major storms of the wet season. Growth of the seedlings is slow initially but increases as roots develop. Growth is very slow or absent during the dry season.

In its native environment (India) it is a relatively slow growing tree, gaining a height of 10 m in about 55 years. In India Cutch Trees lose their leaves in January and February, with new leaves appearing in April-May and completely covering the tree by June-July (CRC 2003).

Where Is It Found?

Which states and territories is it found?

NT

What areas within states and territories is it found?

To date, Black Cutch has only been found in Darwin in the Northern Territory (CRC 2003).

Where does it originate?

Black Cutch is native to the Indian sub-continent, including Assam and Myanmar (Burma), as far as the lower Himalayan ranges and Afghanistan (CRC 2003).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

NT, QLD, WA

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?

YES

Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?

NO

Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Senegalia catechu

Other scientific names (synonyms)?

• Acacia catechu (L.f.) Willd.
• Mimosa catechu L.f

Does it have other known common name(s)?

Cutch Tree, Catechu, Kher, Cachou, Cutchtree, Black Catechu