Phalaris

Phalaris aquatica L.

Synonyms - Phalaris stenoptera, Phalaris nodosa, Phalaris tuberosa L.

Family: Poaceae

Names:

Phalaris is the Greek for coot with its bald white head or from phalaros meaning white crested. Both refer to the appearance of the seed head.
The common name Phalaris is from the genus name.

Other names:

Australian Phalaris
Harding Grass
Phalaris
Toowoomba Canary Grass.

Summary:

A clumped or densely tufted, hairless, autumn and spring growing perennial grass of wet areas to 1.2 m tall with light blue green leaves, swollen stem bases and cylindrical compact seed heads 15-150 mm long that are composed of numerous densely packed spikelets. Each spikelet is 4-7 mm long.
Native to the Mediterranean, it is a weed of wet disturbed areas, drains and watercourses and flowers in spring and summer.

Description:

Cotyledons:

One.

Leaves:

Bluish green. Mainly basal but also on stems.
Parallel veins. Leaves rolled in the shoot.
Blade - Flat, smooth, 20-500 mm long x 2-14 mm wide, parallel sided, blue green often with a waxy bloom, prominent midrib. Tapers to a fine point. Hard when mature and usually retained on the plant for several months after senescence. Often has prominent stripes. Often drooping when mature. Mid vein often conspicuous on the underside. Hairless.
Ligule - Prominent, membranous, ligule 3-12 mm long, often flat topped or fringed.
Auricles - No auricles, but base of blade winged around stem.
Sheath - Loose. Often does not enclose the stem. Hairless.
Collar - Usually a lighter colour than the blade or sheath.

Stems:

100-1200 mm tall, erect, densely tufted or rarely spreading, stout, stiff, round and hollow with solid, swollen, pale (or pigmented) nodes, often bent at the lower nodes, swollen bases. Hairless.
Has red or pink sap when the stems are cut. Sometimes roots at the nodes. Rarely rhizomatous and produces stems that are spaced apart.
Usually has many stems arising from the base of the plant.

Flower head:

Cylindrical to oblong or narrowly egg shaped, dense, spike like panicle 10-125 mm long x 10-25 mm wide, soft, occasionally lobed at the base. Spikelets clustered on short branches around the central stalk. Silvery white and flaring open when mature with chaffy lemmas that are winged on the back. Somewhat tapered towards the ends and broader below. On the end of a long slender stalk. Often partially enclosed in the top sheath for some time.

Flowers:

Spikelets - Many, 4.4-7.5 mm long, light green to whitish, flattened, chaffy, often in pairs. On short stalks. 3 florets per spikelet but only 1 fertile.
Florets - Upper most one is fertile, 3-4.6 mm long x 1.2-1.5 mm wide. Other 2 are sterile, smaller and different sizes.
Glumes - Almost the same length, 4.4-7.5 mm long x 1-2 mm wide, white with yellow-green stripes. 3 veined with prominent, green side veins. Keeled with broad wings in the upper two thirds. Edges smooth or with fine teeth. Usually hairless.
Palea - 2.5-4 mm long, 2 ribbed. Hairy on the keel, hairless on the sides.
Lemma - All have hairs when young. First lemma absent. Second lemma, sterile, 0.2-2.5 mm long, hairy, pressed against the fertile lemma. Third lemma, fertile, bisexual, one third to almost the same length as the glumes, 3-4.6 mm long, flattened, egg shaped, papery, 5 ribbed, silky hairy when young, glossy, smooth, hairless and hard when old.
Stamens -
Anthers -
Breaks above the glumes.

Seeds:

Light brown. Tear shaped. 1-2.5 mm long x 1.2 mm wide. Smooth and shiny. Awnless.

Roots:

Large fibrous, deep root system.
Loosely branched, short rhizomes crowded around the crown that grows from the mother rootstock to form new daughter plants.
Stems may root at the nodes.

Key Characters:

Prominent, membranous, ligule 3-12 mm long, often flat topped or fringed.
No auricles, but base of blade winged around stem.
Perennial with a rhizome.
Spikelets all fertile and fall singly.
Glumes acute but not tapering into a long point, keel narrowly winged over the upper 2/3, entire or serrulate
Dense, cylindric to ovate-cylindric, chaffy, seed head.
Pink sap when stems are cut.

Biology:

Life cycle:

Perennial. Seeds germinate in autumn to winter and forms a crown of swollen stem bases. These are somewhat drought sensitive in the first season or two but soon develop a deep extensive root system and robust crown allowing them to withstand dry spells. It flowers from late-winter to summer. Crowns send out new shoots in early autumn and grow mainly in the cooler months and die back over the hot, dry summer period. In good conditions they will grow all year.

Physiology

Waterlogging tolerant.
Drought tolerant once established.

Reproduction:

By seed and rhizomes.

Flowering times:

November to January in SA
September to January in WA.
November to January in Victoria.

Seed Biology and Germination:

Vegetative Propagules:

Rhizomes.

Hybrids:

Some commercial cultivars are hybrids including Australian, Siro Seedmaster, Sirocco, Sirolan and Sirosa. Australian is summer dormant, Siro Seedmaster retains more of its seed in the head and Sirocco is more summer active.
Some commercial varieties are crosses between Phalaris aquatica and Phalaris arundinacea.
Aquatic biotypes occur.

Population Dynamics and Dispersal:

Spread by seed and rhizomes. Stands become denser mainly by rhizomes producing new daughter plants close to the parent. New infestations usually arise from seed intentionally planted or carried by water, animals or machinery especially slashers and mowers. Movement along roadsides often associated with soil carrying seed or rhizomes being moved by graders.

Origin and History:

Mediterranean, North Africa, Central Asia, Canary Islands.

Distribution:

ACT, NSW, QLD, SA, TAS, VIC, WA.
New Zealand, South Africa, USA.

Courtesy Australia's Virtual Herbarium.

Habitats:

Climate:

Temperate. In areas with an annual rainfall greater than 450 mm.

Soil:

Moist areas on a wide range of soils. Grows well on deep rich black soils and sandy soils.

Significance:

Beneficial:

Important pasture grass for fodder. Grazing tolerant.
Sown in irrigated pasture areas.
Withstands heavy grazing and waterlogging.

Detrimental:

Weed of crops, pastures, rotation crops, perennial crops, grass land, gardens, vegetables, roadsides, aquatic areas, native grasslands and orchards.
Fire hazard as dead material builds up in the centre of the plants if it is not grazed.
The dense growth habit smothers most other species and prevents recruitment of overstorey species.

Toxicity:

Alkaloids cause "Phalaris Staggers" especially in sheep grazing fresh, shooting pastures or in areas deficient in cobalt. Occasionally occurs in cattle. Highest levels occur after frosting or growth after a stress period or nitrogen fertilisation or in dull humid conditions. Use cobalt bullets for grazing animals. Despite its toxicity it is a major pasture species and causes few problems if carefully managed.
There are 3 forms; Pre acute, acute and chronic.

Symptoms:

Pre Acute
Difficulty breathing, dark colour, sudden death from heart failure when excited. Occurs 5-12 hours after grazing.
Acute
Convulsions, rigid extension of limbs, curling of toes, grinding of jaw, head thrown back, dilation of pupils, ropy salivation, fast irregular heart beat twitching of ears, nostrils and tail, breathing difficulty, dark colour, eyeball rolling, Recovery usually occurs.
Chronic
Walking on knees, uncoordinated gait, nodding of head. Symptoms persist after removal from phalaris. Attacks may pass but are brought on again when the animal is disturbed.

Treatment:

Use a few hungry animals to test the level of toxicity. Expose them to the Phalaris then drive them vigorously and check for symptoms.
Don't graze fresh growth and only graze in the afternoon on fine days.
Seek advice on the use of cobalt bullets.

Legislation:

None.

Management and Control:

Heavy, continuous grazing and regular mowing generally keep it under control.
In cropping areas, Phalaris 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 800 mL/ha glyphosate(450g/L) followed by 800 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 2 L/ha glyphosate(450g/L). Rates should be adjusted so that a total of 3-4 L/ha glyphosate is applied over the 2-4 sprays. This will give results similar to applying 6 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.
Clean mowing equipment to reduce spread to clean areas.
Don't plant Phalaris in close proximity to bushland areas.
Don't throw garden waste into bushland areas.

Thresholds:

Low levels can cause large yield reductions.

Eradication strategies:

Manual control is usually difficult.
If possible burn the infestation then treat the regrowth with herbicides.
Kill rhizomes with 100 mL glyphosate(450g/L) plus 25 mL Pulse® in 10 L of water applied in late winter to spring when plants are growing vigorously before flowering. Use 5 L/ha glyphosate(450g/L) for broadacre sprays. Repeat every 8 weeks or when regrowth reaches about 5 cm tall. Control seedlings with grass selective herbicides in the winter and spring of following seasons.
For example 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.
Small plants can be removed manually after removing and bagging seed heads providing all the rhizome is collected and burnt.
In sensitive areas, the plants may be cut just above ground level and then a mixture of 1 part glyphosate in 2 parts water applied immediately to the base.
Burning and mowing alone usually does not provide control but makes herbicidal control easier. Repeated cultivation can provide some control. Solarisation can be useful in organic areas.
It normally takes 2-3 years of vigilant control to achieve eradication from an area.
In bushland areas, encourage perennial scrub and tree species to reduce light levels. Rapid development of ground cover will effectively compete with the slow growing Phalaris seedlings.
Avoid dumping garden refuse containing these grasses in areas where they may establish.

Herbicide resistance:

None reported.

Related plants:

Blue Canary grass (Phalaris coerulescens)
Canary grass (Phalaris canariensis)
Lesser Canary grass (Phalaris minor)
Paradoxa grass (Phalaris paradoxa)
Reed Canary grass (Phalaris arundinacea)
Phalaris angusta
Phalaris arundinacea var. picta is and ornamental variety.

Plants of similar appearance:

Barley grass (Hordeum leporinum)
Cocksfoot (Dactylis glomerata)
Elephant Grass (Pennisetum purpureum)
Feathertop (Pennisetum villosum)
Hares Foot Grass (Lagurus ovatus) is similar but hairy.
Slender Foxtail (Alopecurus myosuroides)
Marsh Foxtail (Alopecurus geniculatus)
Meadow Foxtail (Alopecurus pratensis)
Timothy Grass (Phleum pratense)
Grasses.

References:

Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P54. Photo.

Black, J.M. (1978). Flora of South Australia. (Government Printer, Adelaide, South Australia). P169.

Blood, K. (2001). Environmental weeds: a field guide for SE Australia. (CH Jerram & Associates, Australia). P218. Photo.

Burbidge, N.T. and Gray, M. (1970). Flora of the Australian Capital Territory. (Australian National University Press, Canberra). P59-60. Diagram.

Ciba Geigy (1981) Grass Weeds 2. CIBA GEIGY Ltd, Basle, Switzerland. P111. Diagrams.

Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne). P130. Photo.

Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney). P340-344. Photo plate 22.

Gardner, G.A. and Bennetts, H.W. (1956). The toxic plants of Western Australia. (West Australian Newspapers Ltd, Perth). P8-9.

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). #960.1.

Marchant, N.G., Wheeler, J.R., Rye, B.L., Bennett, E.M., Lander, N.S. and Macfarlane, T.D. (1987). Flora of the Perth Region. (Western Australian Herbarium, Department of Agriculture, Western Australia). P978.

McBarron, E.J. (1983). Poisonous plants. (Inkata Press, Melbourne). P16-17. Diagram.

Moore, J.H. and Wheeler, J.R. (2002). Southern Weeds and their Control. Photos.

Muyt, A. (2001). Bush Invaders of South-East Australia: a guide to the identification and control of environmental weeds found in South East Australia. (R.G and F.J. Richardson, Australia). P82-83. Photos.

Paterson, J.G. (1977). Grasses in South Western Australia. (Western Australian Department of Agriculture Bulletin 4007). P73. Diagram.

Wilding, J.L. et al. (1987). Crop weeds. (Inkata Press, Melbourne). P30. Diagram. Photo.

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.