Noxious weed

Typically they are plants that grow aggressively, multiply quickly without natural controls (native herbivores, soil chemistry, etc.

Noxious weeds are a large problem in many parts of the world, greatly affecting areas of agriculture, forest management, nature reserves, parks and other open space.

[1] Many noxious weeds have come to new regions and countries through contaminated shipments of feed and crop seeds or were intentionally introduced as ornamental plants for horticultural use.

Some "noxious weeds", such as ragwort, produce copious amounts of nectar, valuable for the survival of bees and other pollinators, or other advantages like larval host foods and habitats.

In the US, wild parsnip Pastinaca sativa, for instance, provides large tubular stems that some bee species hibernate in, larval food for two different swallowtail butterflies, and other beneficial qualities.

[2] Some noxious weeds are harmful or poisonous to humans, domesticated grazing animals, and wildlife.

Protecting grazing animals from toxic weeds in their primary feeding areas is therefore important.

Laws often require that noxious weed control funding from governmental agencies must be used for eradication, invasion prevention, or native habitat and plant community restoration project scopes.

[6] Insects and fungi have long been used as biological controls of some noxious weeds and more recently nematodes have also been used.

Those include pulling the entire weed out of the ground,[8] spraying herbicide if it's a large area,[9] and using machines to turn over the soil.

[10][11] Also, overplanting a native species is a long term solution in eradicating noxious weeds.

[15] In Canada, constitutional responsibility for the regulation of agriculture and the environment is shared between the federal and provincial governments.

[19] An example of highly invasive and phototoxic weeds are 3 related species of hogweed: There are active measures being taken to stop their spread and possibly eradicate them from European environment.

2. c. 54) covers Great Britain,[28] It is mainly relevant to farmers and other rural settings rather than the allotment or garden-scale growers.

These are: The Department for Environment, Food and Rural Affairs (DEFRA) provides guidance for the removal of these weeds from infested land.