Pyp Grass is a vigorous, rhizomatous perennial grass spreading by runners, with tufted cane-like stems to 1.3 m high. The leaves are rough, frequently inrolled with persistent leaf sheaths and a small fringe of hairs between the leaf blade and sheath. The slender inflorescence appears to be one-sided. Each spikelet is 12-15 mm long with 3 florets, but only the upper smaller floret is fertile. The outer segment (lemma) of each lower sterile floret is softly hairy and tapers into a sharp point or very short bristle less than 2 mm long.
Native to South Africa, it was planted as a sand-binding species and is now a weed of coastal sand dunes. It flowers in spring and summer, but rarely sets viable seed.
Description:
Cotyledons:
One
Leaves:
Blade - Dark green, parallel sided, straight, floppy, flat or rolled. 40-70 mm long by 1-4 mm wide, rough to touch. Hairless.
Ligule - Hairy ring.
Auricles - Wavy, often purple, short.
Sheaths - Lowest one bladeless and withering with age. Upper ones tight. Hairless.
Stems:
Slender, tufted, smooth, erect or ascending 300-1500 mm high, cane like. Hairless. 4-6 hairless, often purple nodes. Often kneed at the lower nodes. Roots from the nodes.
Flower head:
Narrow , erect to drooping, red-purple or green panicle, 60-200 mm long. Sometimes branched. Branches and pedicels fine, bent back. Branches tend to hang to one side.
Flowers:
Spikelets - Single, pendulous, egg shaped to oblong, flattened, 12-15 mm long, stalked. 3 flowered.
Florets - 2 lower ones are rough, sterile or empty. Upper one bisexual, shorter.
Glumes - Straw coloured, oblong, thin, persistent, Less than half the length to almost as long as the spikelets, hairless with tiny hairs on the edges. Tip pointed.
Lower one 10-11 mm long, 5-7 ribbed.
Upper one 11-13 mm long, 5-7 ribbed.
Palea - 9.5-10 mm long, translucent, narrow, keeled. Hairless.
Lemmas of empty floret, oblong, leathery, hairy and bearded at the base, 5-7 ribbed, with a pointed tip or a short 1-2 mm long awn. Lower lemma 12-14 mm long, upper one 11.5-14 mm long.
Lemmas of fertile floret, 10-11 mm long, hairy.
Stamens -6 usually.
Anthers - Yellow.
Seeds:
Elliptical, flattened, 12 mm long by 2 mm wide. Surface hairy. Sets very few viable seeds.
Roots:
Often with a robust, creeping branched rhizome. Easily pulled up by stock.
Key Characters:
Perennial.
Panicle less than 300 mm long.
Spikelets 12-15 mm long.
Spikelets with one bisexual floret.
Spikelets all distinctly pedicellate (the pedicels at least one quarter the length of the spikelet)
Lemma of empty floret with long soft hairs.
Adapted from John Black, Flora of SA.
Biology:
Life cycle:
Perennial. Summer growing with rapid growth after spring, summer and autumn rains. Flowers in spring.
Physiology:
Does not withstand heavy grazing.
C3 plant.
Sunken stomata arched over by 4 cuticular flanges and in rolled leaves help reduce water loss. Only the lower surface of the leaf, which has very few stomata, is exposed to the sun and wind
Most roots are infected by mycorrhiza which collect nutrients for the plant.
Deep rhizomes collect water.
Reproduction:
Mainly by rhizomes and rooting at the nodes but possible from seed.
Flowering times:
October and November in Perth.
Spring to summer in WA.
November to January in SA.
Seed Biology and Germination:
Seed production is usually low and probably limited by nitrogen.
Often less than one viable seed per head. Seed production varied from 8 to 276 seeds/m2 in New Zealand.
Vegetative Propagules:
Rhizomes and stems.
Hybrids:
Variety Maxima is probably the only variety in Australia.
Allelopathy:
Population Dynamics and Dispersal:
Spreads mainly by rhizome growth.
In field situations establishment from seed is very low and seedlings are rarely observed.
In New Zealand, Pyp grass spreads about 4-9 metres per year and has tiller densities of 109-172/m2. Each tiller is often more than a metre and up to 2 metres long.
Origin and History:
South Africa.
Introduced and planted for erosion control on beach dunes.
Distribution:
NSW, SA, TAS, VIC, WA.
In WA at Guilderton, Murdoch, Margaret River, Jurien Bay, William Bay, Esperance, Munglinup.
Habitats:
Sandy soils.
Salt tolerant.
Climate:
Soil:
Sandy soils.
Plant Associations:
Significance:
Beneficial:
Used for stabilising sandy and drifting soils especially in coastal situations.
Fodder, shelter.
Detrimental:
Weed of sandy dunes, bushland and disturbed areas.
Serious environmental weed of WA and New Zealand that displaces native species in coastal dune areas.
Toxicity:
Not recorded as toxic.
Legislation:
None.
Management and Control:
Thresholds:
In New Zealand, Pyp grass halved the number of plant species present in the areas it had invaded.
Eradication strategies:
Selective herbicides are the best option for Pyp grass control because they will remove the weed slowly allowing other vegetation to take over and prevent erosion. Use 1.5 L/ha Verdict®520 plus 1% spray oil applied in spring with a back pack mister or 30 mL Verdict®520 plus 100 mL spray oil in 10 L water for hand spraying. Repeat annually. This treatment will damage Marram grass but is not expected to completely kill it.
In non-selective situations, 100 mL glyphosate(450g/L) plus 25 mL Pulse Penetrant® in 10 L water applied any time the Pyp Grass is actively growing provides good control but usually kills companion species also. Spray until just wet and repeat annually.
Replant with desirable species to prevent erosion.
Herbicide resistance:
None reported.
Biological Control:
None available.
Related plants:
Perennial Veldtgrass (Ehrharta calycina) is a perennial with soft hairs on the lemmas. The glumes are almost as long as the 4-8 mm long spikelet
Panic Veldtgrass (Ehrharta erecta) has very short (<5mm long), hairless spikelets.
Annual Veldtgrass (Ehrharta longifolia) is an annual with a only a basal tuft of hairs on the lemmas. Glumes much shorter than the 10-28 mm long spikelet
See diagrams for relative spikelet characters.
Plants of similar appearance:
Grasses.
References:
Black, J.M. (1978). Flora of South Australia. (Government Printer, Adelaide, South Australia). P98. Diagram.
Harrington, K.C., Hodder, L.M. and Outred, H.A. (1998). Biology and Control of Pypgrass. Proceedings of the 51st New Zealand Plant Protection Conference. P255-259.
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). P54-55. Photo.
Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).
Lazarides, M. Cowley, K. and Hohnen, P.. (1997). CSIRO handbook of Australian Weeds. (CSIRO, Melbourne). #374.5.
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). P958.
Acknowledgments:
Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.