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Description

African lovegrass, also commonly known as weeping lovegrass, forms large, unpalatable perennial tussocks (grouped grasses) that grow between 30 and 120 cm high. Leaves are up to 30 cm long and narrow (3 mm wide) with rolled margins. Leaf colour varies from dark green to blue-green.

The flower stems are slender, erect and sometimes arching giving them the “weeping” look. The flower heads form an open panicle (cluster) 6 to 30 cm long with a dark grey-green colour. Ripe seed are present from January to March. Seeds germinate in autumn or spring and are viable for 1 to 5 years.

Similar species

African lovegrass is one of many Eragrostis species, both introduced and native. It can also look similar to other native tussock grasses like Poa and Austrostipa species. Green Adelaide can assist with identification if needed.

Impacts

African lovegrass is highly invasive in grasslands but also in heathlands, woodlands, forests, and riverine environments. It is capable of dominating ground flora causing major displacement of native species and productive plants in pastures.

Considered an early coloniser in disturbed sites particularly along roadsides, African lovegrass can move into pasture areas quickly. It recovers rapidly after fire, is drought tolerant, and forms large swards that increase fire intensity resulting in loss of native flora and fauna.

Mature African lovegrass is unpalatable to stock, which results in selective grazing that reduces desirable pasture species and carrying capacity but favours the weed, increasing size of infestations. If unchecked, it can spread and form pure, dense infestations.

Distribution

African lovegrass was introduced from east Africa as a pasture plant and is widely distributed in Australia. It requires an annual rainfall of at least 400 mm and can be found on a range of soil types.

In South Australia, African lovegrass is mainly restricted to the sides of major roads and some grazing properties. It is present on highways and main roads around Adelaide and some dryland reserves.

Seeds can be spread by wind, water, animals, machinery, vehicles and in contaminated hay and soil, assisting with the establishment of new infestations. Slashing is the main means of spread throughout the Adelaide area.

Control

African lovegrass is a declared weed under the Landscape South Australia Act 2019. The sale of African lovegrass or contaminated goods; and its movement on a public road are prohibited. It is the responsibility of the land owner to control these plants on their property.

Green Adelaide encourages the control of African lovegrass where there is a risk to biodiversity assets and agricultural enterprises.

The leafier and less weedy cultivar for pastures, Eragrostis curvula ‘consol’, is excluded from the declaration.

Control methods

Hygiene

To prevent the spread of African lovegrass, avoid working in infested areas except for control work, and do not remove seeds or plants from infested areas, unless disposing of appropriately. Any control work should be undertaken prior to seed set.

Do not buy or sell contaminated fodder and always decontaminate stock prior to moving. Thoroughly brush down equipment, clothing, machinery and vehicles when leaving an infested area.

Mechanical

Grubbing or digging out of plants is effective for small isolated populations and can be done any time of the year. Soil disturbance in infested areas should be minimised to avoid creating opportunities for African lovegrass seed to germinate.

Repeated mowing prior to seeding can reduce seed production.

Controlled grazing

Young plants are nutritious and are readily grazed by stock thereby reducing plant density and seed production. As plants mature they become unpalatable to stock and they will then graze on competing pasture species. Manage grazing so plants cannot grow to a stage where they become unpalatable.

Chemical

Foliar herbicides (weedkillers) can be spot sprayed on individual plants present in areas of native vegetation or on roadsides during active growth. Chemical treatment is most effective on larger infestations when combined with pre-mowing and then spraying of regrowth. Avoid spraying native plants.

For larger infestations where no native grasses are at risk, soil residual herbicides are effective when applied prior to or at early active growth. This can significantly reduce follow-up control because it suppresses the growth of new seedlings. Sufficient rain is required to wash the herbicide into the root zone but not too much to wash it away.

For advice on chemical options please refer to Controlling declared weeds in SA.