What defines a plant as a weed?

Answer 1

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 such as gardens, lawns or agricultural areas, but also in parks, woods and other natural areas. More specifically, the term is often used to describe native or nonnative plants that grow and reproduce aggressively. 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.

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. A number of weedy species have developed allelopathy, chemical means to prevent the germination or growth of neighboring plants.

Answer 2

The best defintion I ever heard for a weed was a plant that's growing where you don't want it. So, if you want a spotlessly green yard, a dandelion will be a weed. In the same vein though, a rosebush could be a weed if you didn't want it there.

Answer 3

The weed is but an unloved flower whose virtues are misplaced. Hedgemaids, Witch's Taper Mullein, Cow's Parsley & Fairy Candles all adorn the meadow as wildflowers and my garden as weeds.

Answer 4

A weed is simply a misplaced flower

Answer 5

I think if its not something pretty then it must be A weed.

Answer 6

i think it is in the eye of the beholder
one might see a flower when somone elses see a weed

Answer 7

When police officers arrest you, its not a plant your smoking, its a weed.

Answer 8

lol, if you can smoke it its a weed plant! lmao j/k any unwanted plant in a certain area is a weed!

Answer 9

If its overgrown or multiple in quantity. Same as animals but we call these overpopulated animals pests.

Answer 10

http://www.marijuanaseedbanks.com/images/marijuana_leaf_pics/images/weed_plant.jpg

PIECE OF CAKE.