Evergreen perennial which prefers wet ground and spreads by seed. The upright, cylindrical leaves are more akin to stems with a dark green outer layer and a white pithy core. The olive-green flowers sprout from the side of rounded stems some way down from the pointed tip. The whole plant develops into a dense tuft up to 100cm in height, with tenacious roots, but they are fibrous and do not creep around, so the plant remains in a clump.
It is well adapted to wet ground and becomes the predominant species in boggy land. It is not very palitable so on grazing land the dense tufts stand out very noticeably.
Use a fork to loosen the plant or sheer it off just below the surface to remove the growing plate, using a spade, a mattock or a digging hoe - the roots do not regenerate provided no fragments of the growth plate remain. It does not withstand regular close mowing, so the plant will die away if it is shorn to the base and not allowed to regrow. For large clumps a brushcutter blade should cope, a line-cutter will just bounce off. For a large area a rough grass-cutter can be hired.
If the ground is so wet that the grass is declining rushes may come to the fore, as mowing will be less frequent and enough regrowth can occur to maintain the plant. After cultivation the large reservoir of seed will continue to germinate for a few years, but they will not develop under regular mowing conditions.

Weedkillers to use:-
Glyphosate, systemic action killing the whole plant. A few drops of detergent in the mix will help adhesion to the shiny vertical surface. There will be a reservoir of seed so keep a lookout for new seedlings which germinate.

Follow these links for further details on Weeds, Weed Removal and Weed Prevention.