Tuesday, July 06, 2010

The Weed Inspector Visits

The local weed inspector, employed by the Shoalhaven Council, came for a 'visit' the other day.
The council has a list of noxious weeds which the law requires landowners control.
He had had a report that Giant Parramatta Grass had been seen in our vicinity and was doing the rounds to see how big the infestation was.
We walked all over our property and apart from a few juvenile blackberry plants we found nothing. I really try to keep most weeds under control even the ones not on the noxious list.
The blackberry (Rubus fruticosus) is a Weed of National Significance. It was deliberately introduced into Australia in the mid-1800s as a horticultural plant, but early on it was recognised as a serious weed. It is now regarded as one of the worst weeds in Australia because of its invasiveness, potential for spread, and economic and environmental impacts. The plant infests about 8.8 million hectares of temperate Australia.

It has invaded the banks of watercourses, roadsides, pastures, orchards, plantations, forests and bushland throughout temperate Australia. On farms blackberries reduce pasture production, restrict access to water and land, and provide food and shelter for pest animals such as foxes. Other impacts are increased fire hazards caused by the large amount of dead material present in blackberry thickets and a substantial decrease in property values where heavy infestations occur.
He was back a few hours later to say he had found Giant Parramatta Grass (Sporobolus fertilis) by the roadside and in a neighbour's property and that we should be keeping an eye out for it next season as it seeds profusely and easily.
This weed favours sites with compacted soil, such as road verges and tracks, but it will also invade pasture and sandy coastal sites. It has very low feed value, and being very tough, can loosen the teeth of stock feeding on it.

He also said there was African Lovegrass (Eragrostis curvula) in the vicinity. This weed thrives on sandy low nutrient soils, by the roadside, on reserves and over-grazed pasture. It can also invade forest along tracks. It is avoided by livestock and replaces more palatable species in grazed pasture. It is highly flammable and creates a fire hazard.

Another of his main concerns was Fireweed (Senecio madagascariensis). I had had an outbreak of this some years ago (I think it came in with hay) but had not seen it for a couple seasons. It took me three years to get rid of the outbreak. It was a matter of physically pulling out each plant during its growing season and then bagging and burning the collection.
It is toxic to stock eventually causing fatal 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.
Apparently the area around Ulladulla is the only one in the Shoalhaven now entirely free of this curse. The pasture around Nowra can be a sea of yellow during the flowering season.
Guess it will only be a matter of time until we are fighting against it on a regular basis.

No comments: