For many years locals have protested to the RMS and to local council's for their failure to control the fireweed that is located in highway road reserves adjacent to paddocks. Fireweed is declared noxious in the Southern Tablelands and South East Region in all except Queanbeyan and Illawarra LCAs, in class 4.
It is toxic to stock, causing progressive liver damage. It is not readily grazed except by sheep and goats which tolerate the toxins better than other stock. Each plant can produce hundreds of seeds and density in pasture can become very high, greatly reducing carrying capacity.
Fireweed will grow in pasture, on road verges and in native grassland, woodland or forest, but it is most invasive in grazed pasture, where there is bare soil present for seedlings to become established on. Note in photo 3 above the difference in fireweed numbers between the grazed paddock and the densely grassed road verge.
Seed is very fine and wind-blown, and also moved around in soil and on vehicles. It is beginning to invade the tablelands from the south coast where it is well established in pockets and continually expanding its range, south from the Sydney and Illawarra areas and north from Bega Valley.
Most growth occurs after rain, at whatever time of year this occurs. Plants are frost tolerant and can grow through the winter, to flower and seed in spring, but rain at any time will trigger another flush of growth and seeding.
The most effective way to control fireweed is to hand-pull the plant as soon as the plants become visible by beginning to flower. Bag the whole plant for safe disposal or just the flowers and seed heads. It is safe to leave the plant with the flowers pulled off lying on the ground if grass length is sufficient that the plant will be held clear of the ground, or conditions are dry. If the ground is wet and the grass is very short it would be safer to bag and remove the whole plant, though this does create disposal difficulties. Check for seedlings in the vicinity of the more visible plants. Larger infestations can be spot sprayed or boom sprayed with a selective herbicide however for the RMS this is cost prohibitive.
Locals also continue to request the RMS control by slashing. While this can reduce seed set, it is generally not recommended as a method of control as it only prolongs the life of the plants, which would otherwise die after producing seed. The general guidance in lieu of the RMS not controlling fireweed in highway verges is for landowners to maintain vigorous pasture growth that will reduce the number of seedlings which can become established, so farmers are advised to avoid over-grazing. Eurobodalla Council have reported in their Delivery Plan that Council’s weed control program has targeted Bitou Bush, African Love Grass and Fireweed saying "Dry conditions have not been conducive to control a wide range of plant species such as lantana. Inspections for biosecurity matter (weeds) commenced in October 2019 and will target 862 properties."
http://www.southeastweeds.org.au/ say "The native kangaroo grass appears much more resistant to infestation than exotic pasture such as kikuyu or ryegrass, and managing native pastures in vigorous growth may be a good long-term strategy for keeping this weed at bay. Because the plant is wind-dispersed, planting windbreaks across the direction of the prevailing wind and allowing grass growth beneath the trees may be effective at intercepting much of the incoming seed, giving a smaller area to search for seedlings, with the dense grass and strong competition for soil moisture provided by the trees providing a less hospitable seed bed for the weed."