| Revision as of 11:07, 3 April 2004 view sourcePollinator (talk | contribs)Extended confirmed users14,258 edits =Weeds that aren't weeds=← Previous edit | Revision as of 17:34, 3 April 2004 view source Marshman (talk | contribs)Extended confirmed users9,354 edits You are making an important point, but I think you misread the definitionNext edit → | ||
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| '''Weed''' is the generic word for a ] growing in a spot where it is not wanted. The most prominent use of the word is in connection with ], where weeds may damage ]s when growing in fields and poison domesticated ]s when growing on ] land. | '''Weed''' is the generic word for a ] growing in a spot where it is not wanted. The most prominent use of the word is in connection with ], where weeds may damage ]s when growing in fields and poison domesticated ]s when growing on ] land. | ||
| Many weeds are short-lived annual plants, that normally take advantage of temporarily bare soil to produce another generation of seeds before the soil is covered over again by slower growth; with the advent of agriculture, with extensive areas of ploughed soil exposed every year, the opportunities for such plants have been greatly expanded. | Many weeds are short-lived annual plants, that normally take advantage of temporarily bare soil to produce another generation of seeds before the soil is covered over again by slower growth; with the advent of agriculture, with extensive areas of ploughed soil exposed every year, the opportunities for such plants have been greatly expanded. | ||
| ⚫ | The notion of "wanted" is of course entirely in the eye of the beholder. Some people love dandelions for their yellow buttons, like gold coins on the ground. A weed in one situation might be a wildflower in another. Children enjoy blowing the puffball seed heads that form on the dandelion; and adults might utilize the dandelion root as a ]. In fact you can even find dandelion greens for sale in certain restaurants or grocery stores in the United States. Yet the caretaker of a ] will generally regard the dandelion as a troublesome weed. | ||
| === Noxious weeds === | === Noxious weeds === | ||
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| In order to reduce weed growth many ] strategies have been developed. The most basic is ]ing, which cuts the roots of annual weeds. In modern times, chemical weed killers known as ]s have been widely used; they have caused some environmental damage, and efforts are being made to reduce the use of such substances (see for example ], ]). | In order to reduce weed growth many ] strategies have been developed. The most basic is ]ing, which cuts the roots of annual weeds. In modern times, chemical weed killers known as ]s have been widely used; they have caused some environmental damage, and efforts are being made to reduce the use of such substances (see for example ], ]). | ||
| === Weeds that aren't weeds === | |||
| ⚫ | The notion of |
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| Plants that are often considered weeds include: | Plants that are often considered weeds include: | ||
Revision as of 17:34, 3 April 2004
This article is about unwanted plants. Other meanings: the town of Weed, California; Weed music distribution service and Marijuana.
Weed is the generic word for a plant growing in a spot where it is not wanted. The most prominent use of the word is in connection with farming, where weeds may damage crops when growing in fields and poison domesticated animals when growing on pasture land. Many weeds are short-lived annual plants, that normally take advantage of temporarily bare soil to produce another generation of seeds before the soil is covered over again by slower growth; with the advent of agriculture, with extensive areas of ploughed soil exposed every year, the opportunities for such plants have been greatly expanded.
The notion of "wanted" is of course entirely in the eye of the beholder. Some people love dandelions for their yellow buttons, like gold coins on the ground. A weed in one situation might be a wildflower in another. Children enjoy blowing the puffball seed heads that form on the dandelion; and adults might utilize the dandelion root as a herbal medicine. In fact you can even find dandelion greens for sale in certain restaurants or grocery stores in the United States. Yet the caretaker of a lawn will generally regard the dandelion as a troublesome weed.
Noxious weeds
A Noxious weed is a plant that is growing in such a manner that it is causing problems by interfering with other desirable plants or contaminating the harvest of useful plants. Noxious weeds are especially problematic weeds because they spread rapidly, are hard to kill, are toxic to cattle and/or humans, or cause other serious problems. Generally (but not always) noxious weeds are invasive species. In the US and Canada, government agencies, usually within the federal, state or provincial departments of agriculture maintain lists of noxious weeds, and the term has legal significance. It is usually unlawful to transport these weeds or their seeds.
The teasel, for example, was a plant widely grown because it was used to manufacture woolens. It is no longer needed for this purpose but grows everywhere ("Growing everywhere" does not make it a noxious weed). Thus it has become a noxious weed.
Invasive species
Other plants have become weeds by being transferred by human action to locations where they have no natural grazing predators; the classic case is the prickly pear (Opuntia stricta), which overran vast areas of Australia until a moth, Cactoblastis cactorum was introduced. This is frequently quoted as the classic example of successful biological pest control, eliminating >90% of the prickly pear infestation within 10 years.
In cases like the prickly pear in Australia, the weeds are termed invasive species (or exotic invasives). This term is applied when a plant is an introduced species that invades and disturbs natural ecosytems, displacing species native to the target ecoregion and causing harm.
Control
In order to reduce weed growth many weed control strategies have been developed. The most basic is ploughing, which cuts the roots of annual weeds. In modern times, chemical weed killers known as herbicides have been widely used; they have caused some environmental damage, and efforts are being made to reduce the use of such substances (see for example genetic engineering, organic gardening).
Plants that are often considered weeds include:
- Dandelion
- Giant salvinia
- Goutweed
- Japanese knotweed
- Kudzu
- Water hyacinth
- Johnson Grass
- Dock
- Plantain
- Purple dead nettle
- Henbit
- Shepherd's purse
- Cleavers
- Thistle
- Lambsquarters
- Violets
- Quackgrass
- Crabgrass
- Sunflower
- Hairy vetch
- Milkweed
- Queen Annes Lace
- Wild Onion
- and many more
See also: weedy species, weed control, herbicide, pesticide