Quick Facts

Quick facts

• Fireweed (Senecio madagascariensis) is an introduced weed that competes strongly with pasture species and is toxic to livestock.
• It can dominate pastures.
• It is responsible for illness, slow growth and poor conditioning of cattle and can result in death.
• Fireweed is a weed of both arable country and rangelands.

What Does It Look Like?

What is it?

Fireweed (Senecio madagascariensis) is an annual or a short-lived perennial that can vary greatly in size and shape depending on environmental conditions. In dry, harsh conditions it may be less than 20 cm tall with narrow leaves, no branching and few flowers. In ideal conditions it will grow to 50 cm tall with multiple branches, long wide leaves (6 cm x 2 cm) and about 100 flowers. The leaves are alternate and sessile. The blade of the leaf is 2 – 6 cm long and dark green with serrated margins. The leaf base tapers and clasps the stem, often with ear-like lobes in the upper branches.

Flower heads are in loosely aggregations and are bright yellow, radiate, and 3.5 – 4 mm in diameter. There are 13 – 15 marginal (ray) florets per head with the rays ('petals') 6-10 mm long.

'Seeds' (achenes) are up to 100 per head, and are cylindrical, 2 – 3 mm long and surmounted by a pappus of silky hairs 4 – 6.5 mm long (Land Protection 2006; PlantNET 2007)

For further information and assistance with identification of Fireweed contact the herbarium in your state or territory.

Flower colour

Yellow

Growth form (weed type/habit)

Herb

Where it currently grows? Preferred habitat

Fireweed is generally found on roadsides, in pasture, and adjacent open forest and prefers areas of bare soil to become established. It needs moist conditions for seedling establishment, but will grow and flower at any time of year other than mid-winter, given the rainfall. From germination to flowering can take as little as 6 weeks. Plants behave as annuals in southern areas, because they are frost tender, but may over-winter and behave as short-lived perennials further north (Miles undated).

Are there similar species?

There are many other weedy yellow daisies. Most of these consist of a single basal rosette and flower stalks arising from the centre, rather than having a bushy, branched habit. Their flowers tend to be a deeper yellow than those of Fireweed (Miles undated; PlantNET 2007).

There are also numerous native herbs in the genus Senecio. Among these, Fireweed can be distinguished by its 13-15 'petals', and fibrous root system. Two very similar natives are Senecio pinnatifolius var. maritimus which occurs on sea cliffs and dunes and has fleshier leaves and a taproot, and S. pinnatifolius var. lanceolatus which occurs in wet grassy forest along the top of the coastal escarpment. The latter has a more spreading, lax habit than the weed and slightly larger flowers. Senecio madagascariensis may also occur behind beaches or on top of the escarpment, so check the appearance of the plant as well as the location before making an identification (Miles undated; PlantNET 2007).

The large clumping native perennial, Senecio linearifolius, can behave in a weedy way around the edges of the farming areas, where it colonises after fire or other disturbance. If in doubt, get a specimen professionally identified (Miles undated; PlantNET 2007).

Why Is It A Weed?

What are its impacts?

Fireweed is a Weed of National Significance (WONS). It is regarded as one of the worst weeds in Australia because of its invasiveness, potential for spread, and economic and environmental impacts.

Agriculture: Fireweed is an introduced weed that competes strongly with pasture species and is toxic to livestock, causing liver damage. It is responsible for illness, slow growth and poor conditioning of cattle and can result in death. All growth stages contain pyrrolizidine alkaloids that damage the liver. Fireweed is toxic when green or dry therefore contaminated hay or silage may be toxic. Fireweed is generally unpalatable to cattle, so poisoning is most likely to occur when Fireweed plants are dense and stock can not feed selectively, or when there is a shortage of pasture and hungry stock are less selective about food. Sheep and goats are less susceptible to Fireweed poisoning and can graze in Fireweed infested paddocks for at least one season. Toxins found in Fireweed are able to taint the milk of goats that graze this plant. Goats for milk production should not be allowed to graze in Fireweed infested paddocks (Land Protection 2006).

How does it spread?

An average Fireweed plant can produce over 10 000 seeds each year. Fireweed has a shallow branched tap root with many fibrous roots. The shallow roots often allow plants to fall over in wind. When this happens the stem will sprout roots wherever it remains touching the ground (Miles undated).

Most dispersal of seed is by wind movement, but some seeds may be spread by animals, vehicles and in contaminated agricultural produce (Navie 2004).

What is its history in Australia?

Fireweed was first recorded in Australia in the Hunter Valley in 1918. It is not known how it was introduced but it could have been brought in privately as a garden plant. It spread slowly at first but in the last 30 years it has rapidly increased its range, most likely aided by modern transport and rural practices (Land Protection 2006).

How To Manage It?

Best practice management

The best approach to Fireweed control is to prevent it establishing by ensuring that there is a dense cover of pasture in autumn and winter. Waiting until autumn to begin pasture improvement will worsen the Fireweed problem because Fireweed, which germinates in autumn, will be promoted ahead of the pasture by fertilising and direct drilling of winter pasture species. When small infestations of Fireweed are identified, act immediately to prevent the situation from becoming worse and to increase the likelihood of eradication (Land Protection 2006).

Chemical control: Herbicides are most effective if sprayed before plants reach maturity. However, application during flowering will be effective if higher recommended rates of herbicide are applied. Trials have shown herbicide application in the autumn period during April provides good control (Land Protection 2006).

Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au.

Non-chemical control: Plants can be chipped out as long as they are bagged and burnt or disposed of at council approved land fill tips.

You should not burn plants in household wood burning stoves or heaters. Remove chipped out plants from paddocks because they may still set seed and poison stock (Land Protection 2006).

Slashing is usually not effective as it may lead to increased stock poisoning. Slashing tends to give a good visual effect because it removes the flowers but at best it delays flowering and seeding and at worst it damages the pasture, making conditions more favourable for Fireweed. Fireweed remains toxic after being cut and becomes more attractive to stock and thus more likely to cause poisoning (Land Protection 2006).

Biological control: Fireweed has also been recognised as a target for biological control through a cross-jurisdictional government process. This allows activities to be undertaken to develop effective biological controls. A number of organisms can be found attacking Fireweed, but any effect they have is temporary and isolated. An orange rust (Puccinia lagenophorae) is common and often affects Fireweed particularly in lower country. The blue stem borer moth, (Patagoniodes farinari) is also common, but the larvae usually develop too slowly to have an impact. Two moths imported from Madagascar were host tested. In controlled tests they were found to feed important non-target plants so no releases were made and all these insects were destroyed. Other potential biological control agents have been identified, but rigorous testing is needed to ensure that they do not feed on closely related Australian native plants (Land Protection 2006).

Does it have a biological control agent?

YES

When does it grow? (lifecycle/growth calendar)

Fireweed can be an annual, but many plants do survive through the summer so plants of all ages can be present at the same time. Seeds germinate in mild, warm conditions in the presence of light and moisture. Most seedlings appear between March and June then grow quickly to produce their first flowers in 6 – 10 weeks. Fireweed usually begins to die back in spring. The top growth dies, leaving the base and the roots which can last through the summer and re-grow in the following autumn. Depending on rainfall some plants continue to grow and produce flowers and seed through summer. A dry summer followed by autumn or winter rains leads to heavy Fireweed infestations (Land Protection 2006).

Where Is It Found?

Which states and territories is it found?

NSW, QLD

What areas within states and territories is it found?

This species is distributed mainly in the coastal and sub-coastal areas of New South Wales and southern Queensland (Navie 2004). Fireweed is a weed of beef and dairy pasture east of the Great Dividing Range and is currently established along the entire New South Wales coast and north to Brisbane. Isolated infestations have been found in Queensland near Caboolture, Cooroy, Belli Park, Maleny, Yandina, Pelican Waters and as far north as Gympie. Similarly, isolated occurrences have been found on the Western Slopes and Western Plains of New South Wales (Land Protection 2006). It has also been recorded in the Australian Capital Territory, Victoria and Western Australia (Navie 2004).

Fireweed is spreading northward and has the potential to infest extensive areas of valuable pasture north of Brisbane. A prediction based on climate and land use, suggests that Fireweed has the potential to be a serious pest as far north as Rockhampton (Land Protection 2006).

Where does it originate?

Fireweed is native to Madagascar and southern Africa (Land Protection 2006).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

YES

Where is it a declared weed?

ACT, NSW, QLD, WA

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?

NO

Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?

NO

Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Senecio madagascariensis

Other scientific names (synonyms)?

Does it have other known common name(s)?

Madagascar Ragwort, Madagascar Groundsel