Dictionary:

weed¹

  (wēd)

1. 1. A plant considered undesirable, unattractive, or troublesome, especially one growing where it is not wanted, as in a garden.
   2. Rank growth of such plants.
2. A water plant, especially seaweed.
3. The leaves or stems of a plant as distinguished from the seeds: dill weed.
4. Something useless, detrimental, or worthless, especially an animal unfit for breeding.
5. Slang.
   1. Tobacco.
   2. A cigarette.
   3. Marijuana.

1. To clear of weeds.
2. To remove (weeds). Often used with out: weed out dandelions.
3. To eliminate as unsuitable or unwanted. Often used with out: weed out unqualified applicants.

To remove weeds.

[Middle English, from Old English wēod, herb, grass, weed.]

1. A token of mourning, as a black band worn on a man's hat or sleeve.
2. weeds The black mourning clothes of a widow.
3. An article of clothing; a garment. Often used in the plural.

[Middle English wede, garment, from Old English wǣd.]

For more information on weed, visit Britannica.com.

Etymologically, "weed" derives from the Old English word for "grass" or "herb," but during the Middle Ages the meaning has changed to indicate an undesirable plant that grows where it is not wanted, especially among agricultural plots. This has historically been the primary meaning of the word, although in the nineteenth century, American writers grew increasingly aware that calling a plant a "weed" was an arbitrary human judgment, as there is no natural category of weeds. In the words of Ralph Waldo Emerson, a weed "is a plant whose virtues have not yet been discovered." Today, biologists tend to share that opinion, since many of the plants that are designated as weeds are, in fact, closely related to popular crops. Indeed, "weed" has fallen out of usage among biologists, although those who study agriculture still find the term useful in discussions of weed control and management.

American weed control only developed out of the manual methods of pulling and hoeing in the early twentieth century, when salts and other chemicals began to be used as herbicides. However, since the 1970s, as environmental and health concerns have been raised, less toxic methods of weed control have been explored, although it has been found that any interference can have unintended ecological effects. For example, the introduction of a natural predator of an unwanted species—termed "biological control"—can devastate other local species or even, by reducing competition, cause a different species to grow out of control.

Moreover, "weed" has recently developed a new meaning in North America as a term that is applied to socalled invasive species, or non-native plants. Throughout the history of the Americas, as people have immigrated they have tended to bring along the flora and fauna of their homeland, thus intentionally—and at times unintentionally—introducing new species to the continents. Some of these non-native species have multiplied to such an extent that they threaten, or have already destroyed, the biological balance of local environments. This problem has been especially pronounced in Hawaii, Florida, California, and New York State. However, the term "weed" is generally not applied to all introduced or non-native plants but rather to those that are doing the greatest harm to biodiversity and are least controllable through human interference.

Scientists have discovered certain common characteristics among many of the most successful invasive species. They tend to be able to flourish in a variety of climactic zones and to reproduce easily and quickly over long periods with small seeds that are less likely to be eaten. However, non-native plants may also have an advantage in that they can exploit unfilled niches in their new lands while perhaps avoiding traditional enemies. Modern mobility and faster forms of transportation are exacerbating the problem in America and around the world.

Some of the most notorious invasive weeds in America today include kudzu, tumbleweeds, and leafy spurge. Kudzu, from Japan and perhaps originally China, is a semi-woody vine that came to dominate much of the American Southeast in the later twentieth century. Its introduction was encouraged by the American government early in the century to help improve soil and stop erosion, and attempts have continued for decades to undo the ecological damage that its widespread planting and subsequent spread have caused.

Tumbleweeds are now considered to be emblematic of the American West, and some tumbleweed species are indeed native to North America, while others originated in Europe and Asia. They do well with little water and were once cultivated in the hopes of being a food source for livestock. Leafy spurge, which was introduced from Europe and Asia in the early nineteenth century, is believed to be harmful to cattle if eaten. As with kudzu, attempts are being made to control tumbleweeds, leafy spurge, and other invasive weeds through biological, chemical, and manual methods to prevent further environmental and economic damage.

The history of American weeds is not only the story of importations and largely unsuccessful attempts to control non-native species, for native American species have also traveled to new lands. Notoriously, native ragweed, whose pollen causes Americans with hay fever to suffer every fall, has made an appearance in Europe, where it is spreading despite attempts to control it.

Bibliography

Van Driesche, Jason, and Roy van Driesche. Nature Out of Place: Biological Invasions in the Global Age. Washington, D.C.: Island Press, 2000.

Zimdahl, Robert L. Fundamentals of Weed Science. San Diego, Calif.: Academic Press, 1993.

1. a plant growing out of place.
2. of horses, see sporadic lymphangitis.

• noxious w. (1) — a plant defined by law as being particularly undesirable, invasive and difficult to control.

1. According to Emerson, “a plant whose virtues have not yet been discovered.” A less generous but more useful definition from the American Heritage Dictionary calls a weed “a plant considered undesirable, unattractive, or troublesome, especially one growing where it is not wanted, as in a garden.”
2. The stems and leaves of a plant, as opposed to its seeds, as in “dill weed.”

This article is about plants specifically called weeds. For other uses, see Weed (disambiguation).

Yellow starthistle, a thistle native to southern Europe and the Middle East that is an invasive weed in parts of North America.

A weed in a general sense is a plant that is considered by the user of the term to be a nuisance, and normally applied to unwanted plants in human made settings like a garden, lawn, or agricultural areas but also to parks, woods and other natural areas. More specifically, the term is often used to describe native or nonnative plants that grow and reproduce aggressively.^[1] Weeds may be unwanted because they are unsightly, or they limit the growth of other plants by blocking light or using up nutrients from the soil. They also can harbor and spread plant pathogens that can infect and degrade the quality of crop or horticultural plants. Weeds may be a nuisance because they have thorns or prickles, cause skin irritation when contacted, or parts of the plants might come off and attach to fur or clothes.

The term weed in its general sense is a subjective one, without any classification value, since a weed is not a weed when growing where it belongs or is wanted. Indeed, a number of "weeds" have been used in gardens or other cultivated-plant settings. An example is the corncockle, Agrostemma, which was a common field weed exported from Europe along with wheat, but now sometimes grown as a garden plant.^[2]

Weedy plants generally share similar adaptations that give them advantages and allow them to proliferate in disturbed environments whose soil or natural vegetative cover has been damaged. Naturally occurring disturbed environments include dunes and other windswept areas with shifting soils, alluvial flood plains, river banks and deltas, and areas that are often burned. Since human agricultural practices often mimic these natural environments where weedy species have evolved, weeds have adapted to grow and proliferate in human-disturbed areas such as agricultural fields, lawns, roadsides, and construction sites.

The weedy nature of these species often gives them an advantage over more desirable crop species because they often grow quickly and reproduce quickly, have seeds that persist in the soil seed bank for many years, or have short lifespans with multiple generations in the same growing season. Perennial weeds often have underground stems that spread out under the soil surface or, like ground ivy (Glechoma hederacea), have creeping stems that root and spread out over the ground.^[3] A number of weedy species have developed allelopathy, chemical means to prevent the germination or growth of neighboring plants.

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Weeds and people

As long as people have cultivated plants, weeds have been a problem. Weeds have even found their way into religious and literature texts as these quotes from the Bible and Shakespeare show:

"Cursed is the ground because of you; through painful toil you will eat of it all the days of your life. It will produce thorns and thistles for you, and you will eat the plants of the field. By the sweat of your brow you will eat your food until you return to the ground,"^[4]

"To thy fair flower add the rank smell of weeds: But why thy odour matcheth not thy show, The soil is this, that thou dost common grow."^[5]

Weeds and human civilization have a long history. Often weedy plant seeds are collected and transported with crops after the harvesting of grains, so that many of these weed species have moved out of their natural geographic locations and have spread around the world with humans. (See Invasive species.) Not all weeds have the same ability to damage crops and horticultural plants. Some have been classified as noxious weeds because if left unchecked, they often dominate the environment where crop plants are to be grown. They are often foreign species mistakenly or accidentally imported into a region where there are few natural controls to limit their spread and population. With the conversion of land to agriculture producing large areas of open soil and human distribution of food crops mixed with seeds of weeds from other parts of the world, many weeds have ideal areas for growth and reproduction. With Humans being the vector of transport and producer of disturbed environments, weedy species have an ideal association with humans and our impact on the globel environment.

A number of weeds, such as the dandelion Taraxacum, are edible, and their leaves and roots may be used for food or herbal medicine. Burdock is common weed over much of the world, and is sometimes used to make soup and other medicine in East Asia. These so-called "beneficial weeds" may have other beneficial effects, such as drawing away the attacks of crop-destroying insects but often are breeding grounds for insects and pathogens that attack other plants. Dandelions besides being a weed in lawns, are one of several species which break up hardpan in overly cultivated fields, helping crops grow deeper root systems. Some modern species of domesticated flower actually originated as weeds in cultivated fields and have been breed by people into garden plants for their flowers or foliage.

Examples

• Broadleaf plantain - perennial, spreads by seeds that persist in the soil for many years
• Burdock - biennial
• Creeping Charlie - perennial, fast-spreading plants with long creeping stems
• Dandelion - perennial, wind-spread, fast-growing, and drought-tolerant
• Goldenrod - perennial
• Kudzu - perennial
• Leafy spurge - perennial, with underground stems
• Milk thistle - annual or biennial
• Poison ivy - perennial
• Ragweed - annual
• Sorrel - annual
• Sumac - woody perennial
• Wild carrot - biennial
• Wood sorrel - perennial

Part of a series on Horticulture and Gardening
Gardening
Gardening • Garden • Botanical garden • Arboretum • Botany • Plant
Horticulture
Horticulture • Agriculture • Urban agriculture • City farm • Organic farming • Herb farm • Hobby farm • Intercropping • Farm
Customs
Harvest festival • Thanksgiving • History of agriculture
Plant protection
Phytopathology • Pesticide • Weed control

See also

• Herbicide
• Introduced species
• Invasive species
• List of beneficial weeds
• Pesticide
• R-selection
• Vavilovian mimicry
• Weed control
• Weedy species

References

1. ^ ISBN 0-7167-1031-5 Janick, Jules. Horticultural Science. San Francisco: W.H. Freeman, 1979. Page 308.
2. ^ http://davesgarden.com/pf/go/1341/
3. ^ http://employees.csbsju.edu/ssaupe/biol327/Lecture/foraging_case_study.htm
4. ^ Genesis 3:17-19 New International Version
5. ^ http://www.infoplease.com/t/lit/shakespeare-sonnets/69.html

External links

• Weed Identification Guide from Virginia Tech (Southeastern United States)

• Common weeds of the northern United States and Canada from Canadian Weed Science Society

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)

Dansk (Danish)
1.
n. - ukrudt, urt, splejs, mager krikke, spinkel fyr
v. tr. - luge ud, fjerne ukrudt, luge ukrudt, udrense
v. intr. - fjerne ukrudt, luge

2.
n. - sørgedragt, sørgebind

Nederlands (Dutch)
wieden, schoffelen, ongewenste elementen verwijderen, onkruid, weed, wiet, sigaret, slapjanus

Français (French)
1.
n. - (Bot) mauvaise herbe, (Bot) herbes aquatiques, (GB) mauviette (péj), tabac (hum), herbe (fam), marijuana
v. tr. - désherber
v. intr. - désherber

2.
n. - habits de deuil

Deutsch (German)
1.
n. - Unkraut, (Slang), Marihuana, Tabak, (Slang) schwächliches Tier, Schlappschwanz
v. - jäten, aussondern, säubern

2.
n. - Gewand

Ελληνική (Greek)
n. - αγριόχορτο, αγριοβότανο, ζιζάνιο
v. - βοτανίζω, ξεβοτανίζω, ξεχορταριάζω, σκαλίζω, καθαρίζω, ξεδιαλέγω, ξεσκαρτάρω

Italiano (Italian)
indumenti, vestiti da lutto, sarchiare, erbaccia, marijuana, smidollato

Português (Portuguese)
n. - erva daninha (f) (Bot.), charuto (m), roupa (f)
v. - capinar, extirpar

Русский (Russian)
сорняк, водоросль, табак, хилый человек, траурная повязка, что-л. нежелательное, полоть, очищать, избавляться

Español (Spanish)
1.
n. - mala hierba, maleza, marihuana
v. tr. - desherbar, escardar, desyerbar, desmalezar, sachar
v. intr. - escardar las malas hierbas

2.
n. - traje de luto, brazalete negro, crespón

Svenska (Swedish)
n. - ogräs, mager stackare, hästkrake, cigarr
v. - rensa (ogräs), rensa bort

中文（简体） (Chinese (Simplified))
野草, 杂草, 除...的草, 剔除, 除草

中文（繁體） (Chinese (Traditional))
1.
n. - 服喪用的黑紗

2.
n. - 雜草;野草
v. tr. - 給...除雜草
v. intr. - 除草

한국어 (Korean)
1.
n. - 잡초
v. tr. - ~에서 잡초를 뽑다, (무용물 등을) 치우다
v. intr. - 잡초를 뽑다, 방해꾼을 제거하다

2.
n. - 미망인의 상복, (모자 등에 다는) 상장

日本語 (Japanese)
n. - 雑草, たばこ, マリファナ, 弱々しい人, 喪服
v. - 雑草を抜く, 抜く

العربيه (Arabic)
‏(الاسم) عشبه ضارة تنبت بين الزرع النافع, نبته مائيه, شخص ضار, حيوان غير صالح للاستيلاد, ثوب (فعل) يزيل الاعشاب الضارة, يغربل, يتخلص من‏

עברית (Hebrew)
n. - ‮עשב רע, עשב שוטה, טבק, סיגריות, חשיש, אדם כחוש וחלש, סוס נחות‬
v. tr. - ‮ניכש עשבים, ייבל, סילק חלקים לא-רצויים, פטר חברה מחברים לא-רצויים‬
v. intr. - ‮שירש עשבים שוטים, ייבל‬
n. - ‮בגדי אבל של האלמנה‬

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