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Why control weeds in grassland - Nufarm Ireland

Reasons to control grassland weeds

Newly sown grass leys are particularly susceptible to weed competition especially when clover is part of the mix. A 10% infestation by a species such as Dock can result in a 10% reduction in yield. Similar reductions can occur with Thistle infestations.

Permanent grassland will succumb to patches of Docks, Nettles, Thistles and other weeds reducing grazing area and yield of silage or hay.

Weed infestation will reduce palatability which results in selective grazing and accelerates sward degeneration.

Long term leys will degenerate as weed grasses take over.

Weeds poisonous to livestock such as Ragwort represent a major threat to livestock.

Most weeds can produce thousands of seeds which can germinate and cause problems over many years. One Ragwort plant can produce more than 100,000 seeds which can parachute quite long distances.

Noxious weeds

Useful links:
Teagasc fact sheet noxious weeds

The Noxious Weed Act 1936
The weeds listed below can spread very quickly and threaten farmland. Any person responsible for land on which these weeds are growing is liable, upon conviction, to be fined. A person responsible for land may be either the owner, occupier, user or manager of the land. In the case of public roads, parks etc. local authorities have similar obligations.

Common Barberry
Male Wild Hop
Spring Wild Oat

Common weeds known to be poisonous to livestock

The weeds listed below can cause harm to livestock. If these weeds are sprayed it is vital to allow them to die and decay before re-introducing livestock. These weeds remain toxic when made into hay or silage.


Field horsetail