Weed of the Month – Fireweed

Fireweed’s yellow blooms hide a toxic risk for animals and pastures.

Watching swathes of yellow flowers spread across pastures like wildfire spells trouble for any livestock or silage producer. For well over a century, farmers have recognised and removed this introduced South African plant (scientifically known as Senecio madagascariensis) from their pastures.

Fireweed is a Weed of National Significance, containing alkaloids that gradually poison livestock whether they are eating fresh plants or contaminated hay. Though they may not seem to readily consume fireweed, even small amounts can build up over time in cattle, sheep, goats and horses, causing a range of symptoms that may end in death. Where livestock avoid fireweed in preference to better grasses it will increase in abundance and reduce pasture productivity.

Fireweed can also be toxic to humans through prolonged skin contact.
Always wear gloves if removing fireweed by hand.

How to identify Fireweed

Fireweed is a herb to 50cm tall, with many branches as it grows. Its leaves are bright green, soft, narrow and around 5cm long. The flowers are easily recognisable daisy‑like yellow flowers with up to 15 petals. Fireweed will flower at any time of year, but mainly in late winter – early spring.

How Fireweed spreads

Seeds appear on white, feathery hairs that blow away in the wind. Each plant may produce up to 18,000 seeds that spread with wind, water and on machinery or in hay and silage. Plants in flower may still develop viable seeds if they are sprayed or pulled out and left on the ground. It is important to treat Fireweed before it flowers or to bag and dispose of any hand removed plants.

Conditions that favour Fireweed

Fireweed will grow in most soil types but dislikes waterlogging. It grows best in overgrazed pastures and disturbed areas, thriving where competitive pasture is removed and soil fertility drops. There are a few native species in the Senecio genus, though they do not invade pasture in the same aggressive manner.

Managing and controlling Fireweed

Managing established Fireweed requires patience and a dedicated yearly program, combining physical management and chemical treatment. Pasture improvement will also help desirable grasses and other groundcovers to compete with Fireweed. A number of insects and diseases have been introduced as biological control for Fireweed however they have not reliably reduced infestations. Ongoing research into biological controls is occurring.

Think you might have Fireweed?

For advice on managing Fireweed, refer to NSW WeedWise for more information and contact Council’s Biosecurity Officer to notify and for support.

Threatened Species of the Month: Brush-tailed Phascogale (Phascogale tapoatafa)

Hidden amongst the treetops of our region is a tiny but mighty hunter with a tail like a bottlebrush and a brutal breeding season where the males do not survive...

Heads up: Magpie swooping season has arrived

Biodiversity Month is a great reminder that our region is home to an incredible variety of plants and animals – including some very protective feathered locals. As spring arrives, so...

Weed of the Month: Mexican Feather Grass (Nassella tenuissima)

Mexican Feather Grass may look like an attractive ornamental grass, but if it escapes from gardens it can become a serious problem for pastures, bushland and roadsides. This highly invasive...

Native Plant of the Month: Plum Pine (Podocarpus elatus)

Plum Pine (Podocarpus Elatus) is a distinctive native conifer with unusual fruit and strong links to our local rainforests. In our local bushland, we have only three species of native...