The CSIRO have recognised 38 Cyperus species.
I have plenty of Cyperus rotundus, and this is what I found on the net.
Grazed to limited extent by horses and cattle but of little forage value.
Fragrant roots used in perfumes.
Tubers are edible and were an aboriginal food source.
Used to bind soil to prevent wind erosion.
Used in Chinese and Indian herbal medicine as a diuretic, anthelmintic and for treatment of coughs, fever and bronchial asthma.
Listed as one of the worlds worst weeds.
A serious weed of horticulture, floriculture, orchards, vineyards, gardens, parks and disturbed areas.
Weed of cultivated crops, rotation crops, perennial crops, grass land pasture, cotton, maize, sugar cane, tobacco.
Interferes with cultivation especially in vineyards and orchards.
Acts as a host for nematodes and insects of agriculture.
I wouldn't think so Christa but I guess it depends where you are talking about. I think most plants that seed profusely can be bad weeds when grown outside their native habitat and in ideal growing conditions. For example locally the Madeira vine is considered one of the worst (by Bushcare groups) because it can take years to get rid of and for widespread infestations almost impossible to eradicate (see here).
That vine does look quite invasive, and I have seen it growing beside the road and covering the nearby trees. Lantana has caused quite a bit of angst among the farming community as well, but I think that nutgrass is growing all over the globe. It does have some uses and one day when I can get up enough courage, and after I get the scrubbing brush out, maybe see what it tastes like. Everything growing on this earth, must have some beneficial properties.
Everything is here for a reason. Sometimes the reasons are difficult to find though.
While nut grass can make seeds its common form of spread is by the 'nuts'. Even using Glyphosate, you can only kill one lot of nuts at a time. I have, with some difficulty and over some years, eliminated nut grass from my property. By digging btw, not by herbicide. It is tough enough to come up freely through a bitumen pavement from a compacted subsoil.
Japanese knotweed, or Fallopia Japonica,
Yes Jeff, I was wondering if there was an animal that may benefit from eating this plant, but with the giant knotweed up to 5m tall, we would need some giraffes. My nut grass problem does seem so bad now.
No nut grass or Japanese knotweed here (knock on wood) but I do have a persistent Madiera vine that keeps coming up despite years of pulling it out and burying it in one of the raised beds.
Does it have a rhizome or a storage part underground? Mercifully I know only the name. Recall an air potato which I kept digging out only to find it came up again. Finally got it about 4 years later.
Not sure Elaine. I am totally stunned each time I see it come up yet again with long periods of "I've killed it this time" in between. If it comes up again I will think about digging down and finding if it does have some underground storage.
That madiera vine, (Anredera cordifolia) is horible, it spreads through disturbance, by stem pieces and aerial potato-like pieces. When it is janked, it drops its small aerial parts and they can stay dormant for a few years. Boiling is one of the remedies, looks like we might have to get the old copper out. The Queensland Government has a site on Agriculture and Fisheries with a section on plants, and this describes the classes of weeds in Queensland. This madiera vine is class 3, and should not be dumped in refuse. I suppose we will have to be vigilant when sharing potted plants with soil etc.
madiera vine can be eaten cooking may be a way of controlling.