border image

Large File 99mb
This Updated Document includes
Another 40 + weeds

Look alikes:
Compare with phasey bean
border image

Siratro biology
Macroptilium atropurpureum
Family: Fabeaceae (Pea family).

Common names: Siratro, Purple bean.


Seedlings – cotyledons are almost circular 8 – 14 mm in diameter with a slightly notched base. Leaves have indented, lighter coloured main and sub-veins and are borne on stems 1 – 2 cm in length.

Leaves - the first true leaves and subsequent leaves are trifoliate 2 – 7 cm long and 2 – 5 cm wide with obvious indented, lighter coloured main and sub-veins. Leaves are borne on stems 2 – 5 cm long. The underside of the leaves is covered with short, dense hairs making it appear lighter in colour. The leaflets are oblong in shape with pointed tips and may develop a wavy edge. The top leaflet has a short stem 5 – 10 mm in length.

Plants – a perennial semi-prostrate plant with long, densely haired stems that are able to climb obstacles and other plants. Plants can form very dense clumps to 3 – 4 m in diameter.

Flowers – are large, pea shaped, 15 – 20 mm in diameter and deep red to burgundy in colour.

Seeds – are in long, narrow pods 5 – 10 cm long by 3 – 5 mm wide, that become light brown at maturity. The pods split when mature and curl, flicking out the seeds that are 3 – 4 mm in length, bean shaped and mottled orange/brown in colour.

Lifecycle/Biology: Plants can emerge, grow and flower year round in a tropical environment.

Ecology: Well adapted to tropical environments. Plants grow well on a range of soil types including heavy clays.

The problem: Siratro is well suited to the northern cotton areas such as Emerald and can become naturalized on channels, road sides etc. It is an aggressive perennial plant that is naturally tolerant of glyphosate and difficult to remove from channels.

Distribution: Siratro is an introduced, and highly desirable tropical pasture species that has become naturalized in pastures and along roadsides in tropical and sub-tropical areas of Australia.

Origin: A native of Central and North America.

Print this page
footer separator image
footer image
© Copyright The Cotton CRC 2012   :    Privacy Policy   :    Disclaimer   :    Sitemap