Grains Research and Development

Sweet summer grass

Sweet summer grass (Brachiaria eruciformis)

Mature sweet summer grass plant
and seed head
(Photo Wilson et al. 1995)

Sweet summer grass, sweet signal-grass. Sweet summer grass is the preferred common name in the subtropics and tropics of Queensland. This is a major weed of crop and fallow in Central Queensland.

Sweet summer grass (Brachiaria eruciformis) is delicate and fine in appearance compared with the major subtropical summer grasses of cropping such as Urochloa and Echinochloa species.

It is distinguished by its colouring. The culms, leaf margins and leaf sheaths are strongly reddish purple, while the leaf blades are dark green. Leaves are 15 to 100 mm long by 2 to 6 mm wide.

Sweet summer grass tends to be a tufted annual grass that may root at the lower joints, giving a sprawling stoloniferous (stem-forming) appearance. The upright growth habit components of the plant reach 300 to 600 mm in height.

The flowering section of the stem is 10 to 80 mm long with three to 14 spikes of short (10 to 30 mm long) florets. Seed-heads do not have the typical ‘signal’ appearance of the other Brachiaria species as they do not droop, instead remaining upright and parallel with the stem. Seeds are purplish, elliptical and about 2 mm long.

Factors that make sweet summer grass a major weed:

  • Can be competitive when it forms dense mats or carpets across areas of cultivation
  • Creates a problem when the remnant plant material impedes emergence of winter crops
  • Prolific seeder
  • Not known to host insects or diseases and at the time of writing, no herbicide resistance has been confirmed in this weed within Australia or overseas (watch this space!)

Further detail about this weed including integrated weed management tactics that could be considered when developing a management plan can be found in the section on problem weeds in the Integrated Weed Management Manual.

Further information

Ecology and biology of common weeds are outlined in section 6 of the Integrated Weed Management Manual.  

Other publications

Managing difficult to control weeds in summer crops (2010) (Proceedings of the 1st Australian Summer Grains Conference, Gold Coast, Australia, 21st – 24th June 2010)

Prolonging glyphosate effectiveness on difficult to control summer weeds (2008), Werth, J. et al. Sixteenth Australian Weeds Conference