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FIREWEED MANAGEMENT Books on Weeds | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| ABOUT Fireweed
-Senecio Madagascar
Poiret-
, a native of Madagascar and South Africa. It has become a serious
weed of pastures of Queensland and New South Wales because
it depresses forage yield and is poisonous to livestock, causing yearly
losses of
A$2 million. Fireweed is a low, upright, branched herb 4–20 inches high. Its narrow, green leaves are up to 21/2 inches long and have margins that are either entire (smooth), serrated, or lobed. Fireweed flowers profusely with small, daisy-like flowers ranging in size from about 3/8 to 1 inch in diameter. Both the petals and the central disk of the flower are bright yellow, and each flower invariably has 13 petals. The flowers mature into white thistle-balls up to 5/8 inch in diameter. Fireweed is prolific. Each flower produces about 150 thistled seeds, and each plant produces an average of 30,000 seeds. Fireweed seeds (a seed type known as an achene) are dry, cylindrical, and slender, are about 1/10 inch long, and are dispersed by wind or hitchhiking on passing animals and vehicles. The seed is long-lived,making fireweed a permanent problem in infested pastures. Fireweed readily invades pastures damaged by overgrazing, drought, or (in Hawaii) the yellow sugarcane aphid (Sipha species). Fireweed seems equally at home in low-elevation, arid pastures as in high-elevation, moist pastures. Methods to control fireweed Biological control. Australian scientists have collected several insects that feed on fireweed. However, because fireweed is closely related to Senecio lautus Forster f. ex Willd., a native Australian plant that is not a weed, the scientists are pessimistic about chances that release of these insects for fireweed control in Australia will be approved (Dr. G. White, personal communication). Cultural control. Australian agronomists recommend pasture management practices that encourage forage growth and vigor, such as controlled grazing and applications of fertilizers. Early action is emphasized because of the fecundity and rapid dispersal of fireweed. Carefully timed mowing may help, but it also may make the problem worse if done at an inopportune time, such as during drought. Sheep and goats are less susceptible than cattle to fireweed poisoning and can be used to graze down fireweed. However, sheep and goats will succumb to fireweed if they eat large quantities over two grazing seasons. |
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| Like most properties in this area, Aracaria has a fireweed problem in late autumn. In June 2003 we manually pulled out fireweed on the grazing paddocks and collected many bags. The weeds were burnt and Linda made a pepper that was distributed across the paddocks. This is what the paddocks looked like after the clearing in June 2003. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| 23.6.03 Lower grazing paddock after fireweed clearing |
23.6.03 Fireweed - close up |
23.6.03 Lower grazing paddock after fireweed clearing |
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| 4th of June, 2004 - this year there is hardly any fireweed on the grazing paddock as can be seen here. I will take another picture later this month. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| No fireweed at this stage | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Fireweed update (Nov. 2004): Still plenty of fireweed left. Incredibly drought resilient. 12mm rain in 6 months. After every rain the fireweed has come back virtually overnight. Growth rate after rain is phenomenal. We keep pulling it out. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| July, 2005 - Fireweed report | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
It has been quite a wet season. Since October we have had over 2meters of rain. Fireweed has been prolific. We have consistently pulled out the weed and burned the seeds. Right now the farm is almost fireweed free. Today I collected maybe 50 - 60 small plants on the whole farm. We are trying to let nothing go to seed. The reduction in weed seems to be very significant.
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