Quick Facts

Quick facts

• Creeping Sensitive Plant (Mimosa diplotricha) is a plant native to Brazil that can be a small shrub or sub-shrub and prostrate, erect or climbing
• IT is potentially one of the most serious weeds of pastures and sugarcane on the wet tropical coast of Queensland.
• Tens of thousands of hectares of Queensland's tropical pastures are now infested.
• Plants seed profusely, a single plant may produce 10 000 seeds in a single season, with seed remaining dormant for more than 50 years.

What Does It Look Like?

What is it?

Creeping Sensitive Plant (Mimosa diplotricha) is variable in habit and longevity. It may be a small shrub or sub-shrub and prostrate, erect or climbing. It is not uncommon for plants to be 2 to 3 m tall, with large stems up to 6 m long being recorded. It may behave as an annual, a biennial or short-lived perennial. Stems are usually much-branched, 4- or 5-angled in cross-section and become somewhat woody with age. They typically have numerous, recurved (backwardly curved), 3-6 mm long prickles. The prickles are also present on the main leaf axis and on the stalks (peduncles) of the flower heads (Cowan 1998; Parsons & Cuthbertson 2001; Smith 2002; Navie 2004).

The bright green compound (bipinnate) leaves are about 10 to 20 cm long., and composed of about 4-9 pairs of branchlets (pinnae). Each branchlet has 12-30 paired leaflets. The individual leaflets are often finely hairy and fold together when touched and at night (Cowan 1998; Parsons & Cuthbertson 2001; Smith 2002; Navie 2004).

The flowers are in globular heads, with 1-3 stalked heads in the junction between the leaf and the stem or sometimes at the end of a branchlet. The flowers are pink or pinkish-violet, about 12 mm in diameter, and on stalks 4-16 mm long.

Fruit form as seed pods which are clustered, with about 10 produced in each flower head. The flat pods are 10-35 mm long and 6-10 mm wide and have prickles on their margins. They commonly have 3-5 one-seeded segments which split apart at maturity. The light brown and slightly glossy seeds are egg-shaped, about 3 mm long and 2 mm wide (Cowan 1998; Parsons & Cuthbertson 2001; Smith 2002; Navie 2004).

For further information and assistance with identification of Giant Sensitive Plant contact the herbarium in your state or territory.

Flower colour

Pink

Growth form (weed type/habit)

Shrub

Where it currently grows? Preferred habitat

Creeping Sensitive Plant grows best in tropical regions with high moisture and quality soils and has a preference for full sunlight. In Australia it usually occurs as a weed of tropical pastures and crops, particularly sugarcane (GISD 2006).

Are there similar species?

Creeping Sensitive Plant is most likely to be confused with other species of the genus Mimosa, such as Giant Sensitive Plant (M. pigra) and Common Sensitive Plant (M. pudica), all three having touch-sensitive leaflets and pink globular heads of flowers. Giant Sensitive Plant is a large, upright shrub growing to about 6 m high, with the much-branched leaves having 6-19 pairs of primary branchlets (pinnae) (compared to 4-9 pairs in Creeping Sensitive Plant), larger pods from 3-12 cm long producing 14-26 seeds (compared to 1-3.5 cm long and producing 3-5 seeds in Creeping Sensitive Plant). Common Sensitive Plant differs from both of these species in that the branchlets (pinnae) of the leaves arise from the one point on the main leaf axis (not in opposite pairs) and the petioles and rachis of the leaves lack prickles (Cowan 1998; Navie 2004).

The Coffee Bush (Leucaena leucocephala) superficially resembles Creeping Sensitive Plant but it does not have prickles or sensitive leaves and its globular flower heads are creamy yellow (Cowan 1998; Navie 2004).

Why Is It A Weed?

What are its impacts?

Agriculture: Creeping Sensitive Plant is an aggressive weed which chokes out cane and other crops, as well as tropical pastures. It grows faster than sugarcane, sending out long spiny stems which quickly smother the crops, not only reducing the yield but also fouling mechanical harvesters. It is unpalatable to stock and, because of its spiny nature, is not trampled by them. In consequence, it tends to smother pastures, its spiny stems producing tangled thickets in which trapped animals die and man can be seriously injured. Tens of thousands of hectares of Queensland's tropical pastures are now infested with Creeping Sensitive Plant and it is potentially one of the most serious weeds of sugarcanes and pastures on the wet tropical coast of Queensland. Although normally not touched by stock a form of this plant (Mimosa diplotricha var. inversa) is palatable and eaten by cattle. It may be toxic to sheep and a report from the Indonesian island of Flores suggests Giant Sensitive Plant is toxic to pigs (Parsons & Cuthbertson 2001).

How does it spread?

After the pods break up the seed of the Creeping Sensitive Plant remain in the fruit segments which float on water or become attached to clothing and animals. Seed is also spread as a contaminant of hay and other agricultural produce, contaminated soil used for buildings and roadwork, and in unclean machinery and vehicles (Parsons & Cuthbertson 2001).

What is its history in Australia?

Creeping Sensitive Plant was present near Tully in Queensland in about 1929. It seems likely that it arrived as a contaminant of imported pastoral seed (Parsons & Cuthbertson 2001).

How To Manage It?

Best practice management

Non-chemical control: Creeping Sensitive Plant is not easily controlled by cultivation, or cutting and burning of mature plants as they regrow rapidly from the crown, and seeds in the soil readily germinate after aerial growth is removed. There is also the practical problem of access to infested areas if fields are waterlogged. However, if access is available, seedlings can be controlled through cultivation and regular slashing of mature plants, which prevents them from seeding (Parsons & Cuthbertson 2001).

Creeping Sensitive Plant has also been recognised as a target for biological control through a cross-jurisdictional government process. This allows activities to be undertaken to develop effective biological controls. Biological control agents have been trialled for this species, including two Brazilian insects specific to the plant. Of these, a sap-feeding bug called Heteropsylla spinulosa has been found to drastically reduce the vigour and seeding of plants. A native, stem-spotting fungus called Corynespora cassiicola also causes defoliation and dieback in hot humid conditions (Land Protection 2006).

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

Does it have a biological control agent?

YES

When does it grow? (lifecycle/growth calendar)

Given suitable conditions, seeds of Creeping Sensitive Plant can germinate throughout the year. In Queensland the main germination period is at the beginning of the wet season in November or December. Growth is rapid, with plants covering an area of 2 to 3 square metres in their first season, and flowering and fruiting may occur just a few weeks after germination. The main flowering and fruiting period is from April to the end of June. Plants flower profusely and a single plant may produce as many as 10 000 seed per season. Seed may germinate regularly, but it may remain dormant for more than 50 years (Parsons & Cuthbertson 2001; Land Protection 2006).

Where Is It Found?

Which states and territories is it found?

QLD

What areas within states and territories is it found?

Creeping Sensitive Plant is confined to Queensland. It is particularly common in high rainfall areas of coastal northern Queensland, from Ingham to Cooktown and around Mackay but is also found in wetter areas in the south-east of the State. The Shires of Cardwell, Cook, Douglas, Hinchinbrook, Johnstone, Mareeba, Mulgrave, Pioneer, Proserpine and Sarina have been recently listed as having major infestations, with heaviest infestations being recorded for Johnstone and Cardwell Shires (Land Protection 2006).

Where does it originate?

Creeping Sensitive Plant is native to Brazil. It is now widely spread throughout the wet tropics of the world, being recorded from Africa, Mauritius, India, Sri Lanka, south-east Asia, Taiwan, Papua New Guinea, Pacific islands and Australia (Parsons & Cuthbertson 2001; Navie 2004; PIER 2007; Weeds Australia, undated).

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?

NO

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

Mimosa diplotricha

Other scientific names (synonyms)?

• Mimosa diplotricha var. inermis (Adelb.) Verdc.
• Mimosa invisa Mart.
• Mimosa invisa f. inermis Adelb. ex R.S.Cowan
• Mimosa invisa var. inermis Adelb.

Does it have other known common name(s)?

Giant Sensitive Plant, Nila Grass, Tropical Blackberry