Invasiveness Assessment - Spiny burr grass (Cenchrus longispinus) in Victoria (Nox)
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Plant invasiveness is determined by evaluating a plant’s biological and ecological characteristics against criteria that encompass establishment requirements, growth rate and competitive ability, methods of reproduction, and dispersal mechanisms.
| Each characteristic, or criterion, is assessed against a list of intensity ratings. Depending upon information found, a rating of Low, Medium Low, Medium High or High is assigned to that criterion. Where no data is available to answer a criterion, a rating of medium (M) is applied. A description of the invasiveness criteria and intensity ratings used in this process can be viewed here. |
The following table provides information on the invasiveness of Spiny burr grass.
A more detailed description of the methodology of the Victorian Weed Risk Assessment (WRA) method can be viewed below:
Victorian Weed Risk Assessment (WRA) method (PDF - 630 KB)
Victorian Weed Risk Assessment (WRA) method (DOC - 1026 KB)
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Common Name: Spiny burr grass
Scientific name: Cenchrus longispinus
| Question | Comments | Reference | Rating |
| Establishment | |||
| Germination requirements? | “Most germination is in spring and early summer but some occurs at any time of the year except mid-winter.” The bulk of germination occurs due to seasonal influences (spring/summer temps). | Parsons & Cuthbertson (2001) | MH |
| Establishment requirements? | “Spiny burr-grass… is a pioneer plant of disturbed sandy soils. Burrs lying on the soil surface rarely produce plants, probably because of low moisture availability to the seed, and possibly because of an inhibiting effect of light.” Optimum growth with additional factors of seed burial and moisture. | Parsons & Cuthbertson (2001) | L |
| How much disturbance is required? | “Spiny burr-grass… is a pioneer plant of disturbed sandy soils.” In the U.S., it aggressively colonises open, disturbed sites in fields, orchards, vineyards, alfalfa, cultivated crops, ditch banks. | Parsons & Cuthbertson (2001) CDFA | ML |
| Growth/Competitive | |||
| Life form? | Annual grass. | Parsons & Cuthbertson (2001) | MH |
| Allelopathic properties? | None documented |  | L |
| Tolerates herb pressure? | Before flowering this grass has some value as a pasture species, and one recommended method of control is to graze it heavily with sheep to prevent seeding. Once the plant has produced burrs, though, it is not consumed. It is still capable of producing seed under normal stocking rates. | Parsons & Cuthbertson (2001) | MH |
| Normal growth rate? | “Spiny burr-grass does not establish readily in pastures, and lucerne, in particular, is very competitive.” “Sandburs compete poorly with dense vegetation and rarely become established in well-managed pastures.” Maximum growth rate may be less than many species of the same life form. | Parsons & Cuthbertson (2001) CDFA | ML |
| Stress tolerance to frost, drought, w/logg, sal. etc? | “Most plants die in autumn or early winter, however, some may survive over a mild winter and produce a further small crop of burrs in spring.” Some tolerance to frost / low temperatures. No documented evidence of tolerance to drought, salt, waterlogging, etc. | Parsons & Cuthbertson (2001) | ML |
| Reproduction | |||
| Reproductive system | Reproduces sexually. No data to confirm method of pollination, but as a grass it is most likely to be cross-pollinating only. | Adair (pers. coms) | L |
| Number of propagules produced? | “… up to 1000 seeds produced per plant.” | Parsons & Cuthbertson (2001) | ML |
| Propagule longevity? | Seeds can remain dormant for up to three years. | Parsons & Cuthbertson (2001) | L |
| Reproductive period? | While some plants may survive a mild winter to produce a small crop of burrs, this species is essentially an annual. Mature plant produces propagules for only one year. | Parsons & Cuthbertson (2001) | L |
| Time to reproductive maturity? | Germinates in spring or summer; burr produced from December to April; most plants die in autumn. Reaches maturity and produces viable propagules in under one year. | Parsons & Cuthbertson (2001) | H |
| Dispersal | |||
| Number of mechanisms? | “The seed is well equipped to spread because of the barbed spines on the burr.” The burrs attach to wool, fur, clothing, bags and other fibrous materials. “Spiny burr-grass was a common contaminant of hay moved in the drought of the early 1980s. Wind plays little part in spread but water is important in the irrigation areas of southern Australia.” Spread by water, animals and machinery. | Parsons & Cuthbertson (2001) | MH |
| How far do they disperse? | Spread by water, animals and machinery. Dispersal may be more than 1 km. | Parsons & Cuthbertson (2001) | H |
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