Repens is from the Latin repe meaning to creep referring to the creeping habit.
Quack grass.
Other names:
Couch
Couch grass
English Couch
Quick grass
Rope Twitch
Twitch
Summary:
Hardy, temperate, perennial turf grass with yellow rhizomes and an erect, narrow seed head, 8-17 mm long with alternate spikelets. The leaves are slightly rough and narrow.
Description:
Cotyledons:
One
Leaves:
Blade - Narrow, flat, thin, rough to touch on top, 60-300 mm long by 6-10 mm wide. Tip pointed. Sides parallel. Base sheathing. Hairless or sparsely hairy on the upper surface.
Ligule - Papery membrane, flat on top, less than 1 mm long.
Auricles - Clasp the shoot.
Sheath - Sheath of lower leaves sometimes hairy.
Stem leaves -
Stems:
100-1000 mm long, stiff, spreading, erect or curved at the base or bent at the nodes. Rhizomatous. Hairless.
Flower head:
Narrow, dark to dull green, loose to dense spike, 50-300 mm long. Tough, persistent axis (rachis). Spikelets single and closely pressed against the axis in shallow, alternate notches in the rachis. Main axis is rarely hairy.
Flowers:
Spikelets - 3-8 flowered, oblong to egg shaped, 10-20 mm long, flattened, stalkless.
Florets - Longer than the glumes. Ovary hairy at the top.
Glumes - Two, 6-12 mm long, lance shaped, firm, persistent. 3-7 nerves. No awns.
Palea -
Lemma - 8-13 mm long including the awn, rounded on the back. 5 faint nerves. Tip pointed or with an awn up to 10 mm long.
Stamens -
Anthers -
Breaks below the glumes usually with the spikelets falling intact. It rarely breaks above the glumes and between the florets.
Fruit:
Seeds:
Roots:
Long, yellowish, creeping rhizomes.
Key Characters:
Lemma about 10 mm long including the awn.
Biology:
Life cycle:
Perennial. Flowers October to March.
Physiology:
Drought tolerant.
Reproduction:
By seed and creeping rhizomes.
Flowering times:
October to March in SA.
Spring to autumn in NSW.
Summer in WA.
Seed Biology and Germination:
Vegetative Propagules:
Rhizomes.
Hybrids:
Allelopathy:
Produces plant toxins that reduce the growth of the noxious weed Wild Teasel (Dipsacus fullonum).
Population Dynamics and Dispersal:
Spread mainly by rhizome fragments and deliberate planting.
Origin and History:
Europe. Temperate Asia.
Distribution:
NSW, SA, TAS, VIC, WA.
Habitats:
Climate:
Temperate.
Soil:
Sandy soils and heavy soils.
Plant Associations:
Significance:
Beneficial:
Lawn and turf grass.
Detrimental:
Weed of vegetables, orchards, vineyards, cultivation, rotation crops, perennial crops, grass land, wetlands and disturbed areas.
A serious weed in other countries.
Toxicity:
Not recorded as toxic.
Legislation:
None.
Management and Control:
In cropping areas, Quick Grass can usually be reduced to insignificant levels by using glyphosate for spray topping, summer weed control and pre plant weed control.
A typical program would be heavy autumn grazing followed by heavy grazing in late winter to spring with stock being removed when the annual grasses start to elongate in spring. When the heads of annual grasses just start to emerge Spraytop with 1200 mL/ha glyphosate(450g/L) followed by 1200 mL/ha 4 weeks later. If summer weeds emerge then spray with glyphosate at a rate appropriate for the weeds. In autumn spray annual weeds when they have reached the 2 leaf stage with about 4 L/ha glyphosate(450g/L). Rates should be adjusted so that a total of 6-8 L/ha glyphosate is applied over the 2-4 sprays. This will give results similar to applying 9 L/ha as a single application. Cultivation, 2-10 days after spraying with a scarifier or using a tyned full cut seeder to plant the crop will provide improved control compared to minimum tillage planting.
Burning, cultivation or grazing alone are generally ineffective but may improve the effectiveness of herbicide treatments.
Multiple spraying with low rates of glyphosate are usually more effective than fewer sprays with larger doses.
Thresholds:
Low levels can often lead to significant crop yield reductions due to direct competition for nitrogen and consumption of early season or carryover moisture.
Dense stands can be allelopathic or release chemicals into the soil that reduce the germination and growth of crops.
Forms patches that tend to exclude most other species.
Eradication strategies:
Burn the grass to reduce thatch and encourage young growth ready for spraying.
Avoid dumping garden refuse containing these grasses in areas where they may establish. Manual control is very difficult and mowing or burning are usually ineffective. Repeated cultivation can provide control. Solarisation can be useful in organic areas.
Herbicides provide the most reliable control.
100 mL glyphosate(450g/L) plus 25 mL Pulse® in 10 L of water applied when the grass is actively growing every 8 weeks over the spring to autumn period or whenever fresh growth is 20-50 mm tall is the most effective control. For broad acre spraying use 6 L/ha glyphosate(450g/L).
Selective control amongst broad leaved plants can usually be achieved by spraying with 800 mL/ha Verdict®520 or 4 L/ha quizalofop(100g/L) or 6.4 L/ha Fusilade®Forte plus 1% spray oil. Use 16 mL Verdict®520 or 80 mL quizalofop(100g/L) or 125 mL Fusilade®Forte plus 100 mL of spray oil per 10 L water for hand sprays.
Painting runners or crowns with 1 L glyphosate in 2 L water is useful in sensitive areas.
It normally takes 2-3 years of vigilant control to achieve eradication from an area.
Herbicide resistance:
Biological Control:
Related plants:
None.
Plants of similar appearance:
Agropyron scabrum is very similar but has 6-12 florets per spikelet.
Couch, lawn and turf grasses.
References:
Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P33. Diagram.
Black, J.M. (1978). Flora of South Australia. (Government Printer, Adelaide, South Australia). P139.
Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne). P51.
Hussey, B.M.J., Keighery, G.J., Cousens, R.D., Dodd, J. and Lloyd, S.G. (1997). Western Weeds. A guide to the weeds of Western Australia. (Plant Protection Society of Western Australia, Perth, Western Australia). P54.
Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).
Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #494.1.
Acknowledgments:
Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.